Pump it up!!!!!

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Pump it up!!!!!

Post  highpressure on Thu 31 May 2012, 9:52 am

Following on from Ricksters Success with steaming I thougth I would have another crack at it today as I have a few days off and theres no-one around,plus the cooler weather means less windows are open etc. So sorted out a few bits to get a sealed boiler and then set about lighting a fire. Now bearing in mind I have had a number of engines and have steamed countless times I have a tried and tested method which produces good results and I am quite relaxed at it. However for the third time it was aborted due to a considerable amount of water dripping through the fire into the ashpan and damping the fire down, not to metion causing me some concern as to the source of the water. Having re-seated the fusible plug with tape I was quite concerned about a leaking tube. Despite being highly improbable someone very clever once said if all the probable causes can be ruled out whatevers is left however improbable is the truth. What a Face

I currently have my brother in laws hydraulic tester here for testing central heating and it can pump up to 435 psi so i thought I would do a cold test under controlled conditions to try and indentify the problem and also to test the rest of the boiler as I have wanted to for some time.

I managed to get to 150psi for about 30 seconds as the pressure just fell away due to EVERY fitting leaking, some quite a lot. And when I say every fitting I mean every fitting, the steam backhead, the globe valve ( in its base, around the stem for the handle ) the drain cocks from both the shafts and the fittings to the cylinder despite being lapped in, the globe for the blower, lifter, all the bushes for the rods..... the list goes on. On the up side the fire box was a dry as a bone so rules out a leak but doesnt answer the question as to the water issue.

Having had a chance to think about the outcome I was wondering if anyone else has firstly tried lighting a fire and had the condensation problem, I have been wondering if it just the fact that the heat combined with the large area of cold steel has caused just a good level of condensation or something else although I haven't seen this on previous engines. I have ruled out the wood being damp as it has been stored in a dry enviroment for at least a year so should not produce that amount of water

Secondly has anyone given some serious thought to the cold water test and the best way to achieve it?? I know I keep banging on about this but none of us will be allowed to steam up in public regardless of age of boiler or condition of finish if we can't produce legal paperwork to cover insurance. That means an independant hydraulic test and hot steam test or an NTET disc which will only be issued when the insurers have that paperwork. Clearly most of the leaks I have regarding the fitting to the cylinder could be eliminated if the pressure unit could be attached in some way to avoid pressurising the cylinder and components but I cant see how to acheive this. Most of the fittings will probably seal up as they get hot and I dont think they are nessecary for the test either.

Can we all get together to come up a way to get this wretched test out of the way or can STW come up with a solution? I have been racking my brains for a few weeks before trying this and had the result I expected. Dont forget we need to get to 270 psi in the boiler cold and hold it for 1/2 hour. We still seem to be in an area that eludes answer and we ALL have to get this done unless you intend to sit in the back garden and not go to events alight. Even when we get the flywheels and bits we can't go out until this is put to bed.

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Re: Pump it up!!!!!

Post  Tim Watson on Thu 31 May 2012, 4:23 pm

Kev
Looks like all your fittings need tightening up and / or more sealant tape. When I do an hydraulic test I tighten up the fittings where appropriate (e.g, regulator, piston & valve glands, globe valves - if leaking, isolate gauge glass, seal exhaust) and then slacken them off a little if they are too tight for running.

There is a tremendous (alarming) amount of condensation associated with a new steel boiler on first steaming. The hydraulic test should include maintenance of pressure for a reasonable period of time, accepting that obvious minor leaks around fittings will cause pressure drop. In this case the pump is used to 'top up' the pressure as required. The boiler itself, the pressure vessel, is closely inspected for leaks e.g. around tubes and stays, whilst the hydraulic pressure is maintained.

Tim

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Re: Pump it up!!!!!

Post  highpressure on Fri 01 Jun 2012, 12:48 am

Hi Tim,

Last night I went into the garage and remade some of the globe valves, i.e. the backhead one, took the whole assembly off and then took the whole valve apart, stem out body apart, re-fitted tape and reassmbled but need to test it over the weekend. Bit disappointed to find that brand new fittings need to be completely rebuilt to get them servicable. Those other fine looking engines nearing completion might get a shock when they try this test.

As to the cylinder fitting I noticed last night that the valve rod gland bush is actually starting to bend where I have tightened it so much and its still not water tight. Not the best thing to see here. The entire cylinder assembly can be left out of the test if a suitable way of getting the pressure into the boiler can be acheived and leave the cylinder isolated, but no-one seems to have a solution for this and it feels a bit like we're just being left to fend for ourselves here at the end of the build for something which is quite an integral part of getting a working engine. I do however understand that the pressures at STW are quite immense what with design of future models, current kit production, delays from third parties, impatient builders waiting for parts etc, but as Steve knows the design best and has experience of pressure testing vessles that are complete and they have the facilities to make almost anything I was hoping that a "kit" for hydraulic testing could perhaps be fabricated to continue to help us in the future. Again unless you pay for an independant boiler tester to do a ten year test, from what I can understand all MES testers have to do the hydraulic test every two years after the initial four year first test. So this is sonething that will keep coming back.

Considering it overnight it would be a fairly simple device, a plate to replace the safety valve as this needs to be eliminated from the test anyway, with a pair of bolts in to hold a small plate down over the regulator hole to seal off the cylinders (probably with a small rubber pad to seal it ). Then the reg rod can be left in place to seal the glands here. The siren hole can be used as the input from the pressure device and then all the leaks are removed from the cylinder fittings, hey presto just the boiler and its fittings tested.

highpressure

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Teething problems

Post  Steve Traill on Fri 01 Jun 2012, 3:42 am

Don't worry so much! all these leaks will sort themselves out, attention to detail is crucial when assembling parts, the PTFE 3mm square rope is good for sealing glands and shouldn't need much more than hand pressure to seal. In fact I double nut all these parts as they're never done up tight enough to lock on so the extra nut holds it in place. If the stud isn't long enough I use a half nut (ordinary nut + hacksaw!).

With the SC Burrell STW supplied a blanking plate to replace the safety valve & I'm sure they will do something similar with the DCC. It would usually arrive in the last kit, it's just everyone is so eager to get steaming! One mod I did to the blanking plate is use the threaded hole for inserting the water, which is in the centre, to put a bolt in to hold down the top of the regulator. This stops water leaking past that and going in the smokebox. I made a little grooved plate to sit on top of the regulator slide as I didn't want any damage to the regulator from the bolt (this only needs to be hand tight, it just stops any lift). It works a treat & hydraulic tests are trouble free now. I drilled a similar hole to connect the hydraulic tester too next to the centre hole. I bought myself a hydraulic tester just so I can do a pretest before setting off for the main one. It was a Rothenberger Hydraulic tester for testing central heating systems and is pretty accurate. It costs about 120 from most good plumbing merchants.

Hope this helps, when first steaming I have a pen & paper to list all the leaks, gradually the list gets shorter with each steaming until you can forget the pen & paper.

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Re: Pump it up!!!!!

Post  highpressure on Fri 01 Jun 2012, 4:13 am

Yes Steve thats the kind of answer I am seeking and what you describe is what I have in mind. I know were all eager to get going and fro those of us who dont have an alternative it is hard!!! But dont forget, as I tried to tell some one last night who commented about being patient etc that the season is over by the end of September which although sounds along way off, with at least another 3-4 weeks wait for the the flywheel et al that gets us well into July, and thats if everything is in that kit to complete for steaming, then the test needs to be done and pretty soon the season is over until next April or May at the earliest, and thats if events aren't rained off. As much as I want enjoy steaming I have certainly done this to drive the engine I would certainly like to partake in some of the local rallies this summer. Whilst I am waiting I can apply some thought to the process of getting a pass without too much hassle and hopefully get things made up or in place to acheive htis quickly once ready.

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Re: Pump it up!!!!!

Post  bjwlancashire on Sun 03 Jun 2012, 4:28 am

highpressure wrote:And when I say every fitting I mean every fitting, the steam backhead, the globe valve ( in its base, around the stem for the handle )

Kev

Just a belated thought about your globe valves leaking around the base of the handle. The flow of steam (or water in your case) in a globe valve is such that if the valve is closed there is no pressure around the stem of the valve as you are screwing down on the pressure trying to come up through the valve. If you put the valve on the steam pipe the wrong way round you will have the area around the handle stem under pressure permanently with steam trying to go down through the valve rather than come up through it. It may be worth just double checking your globe valves are having the steam flow through in the right direction.

With regard to the saftey valve blanking plate, Steve gave me one when I was in STW a couple of weeks ago as I was looking at trying to get Blackbeard tested towards the end of June. I may have to reevaluate this due to a house move in July but you will get the plate but I think it would normally have come with the last kit. I also got the cylinder drawing so I could look at getting a blanking plate made for the whistle hole and the govenor hole. I foyu clamp the regfulator valve shut you should not need to worry about the exhaust outlet.

Good luck in getting all your leaks sorted out and just remember, you don't need to go to an event to steam up even though it is nice to do so in public with other engines. You could always arrange a local get-together with other engine owners. In any case, you will probably need to get used to your new engine and let it bed in.

Cheers

Brian

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Re: Pump it up!!!!!

Post  highpressure on Sun 03 Jun 2012, 7:48 am

Hi Brian,

Useful info on the globe valve hadnt considered it was the wrong way round, you may well be right I will have a look again. Not so bothered about the other leaks now, have a look at the other thread I have just posted. Went to Laughton yesterday and just sat as a static exhibit which I had doen quite a lot towrads the end of last year. your'e quite right of course, nice and relaxed lots of positve comments and got to see the show too, so not too desparate, but the smell of others does't help to calm me down. I imagine kind of like giving up smoking in a pub 10 years ago!!!Good news on the blanking plate I might have to speak to them at STW.

Cheers Kev.

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Re: Pump it up!!!!!

Post  highpressure on Sat 16 Jun 2012, 6:05 am

Made some progress with the hydraulic test prep today but it felt like two steps forward one step back. On the plus side the plate for the regulator worked perfectly and by watching the govenor port it was bone dry. But there were leaks from just about all other fittings despite having taken them apart since the last time and re-taping them with PTFE.

Thanks to Ian at STW his suggestion of liquid thread sealant has helped a treat in selaing some of the leaks and I manged to get to 300 psi for about 2 seconds and then it fell away. The simpling valve needs to be blocked as it wont hold anything back at all and is a right pain to get to, but I made up a rubber gasket and aluminium plate and it worked a treat. I am a bit concerned about how much I have had to do up the lifter valve unions, they are in danger of being distorted and still let by a bit. But the main issue is not one that can be selaed with tape or sealant.. Both the stems to the clacks are letting by the top nut, the balls themselves both seat, but I cant think of how to stop this leak. Also the blow down valve lets by out of the blow down tube, again something that wont be cured by tape the pressure is getting by the stem even when closed.

Has anyone any suggestions as to how to cure these few little niggles and then hopefully I might be able to get a test done. If I understand and remember correctly the boiler needs to hold 1 1/2 times working pressure for 30 minutes according to the southern regs rules. Thats 270 psi which makes for hard work trying to seal this stuff cold.

Still I feel a lot more confident it is within reach now so once these bits are sorted it might be close.

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Today is a good day :)

Post  highpressure on Wed 20 Jun 2012, 5:41 am

Been working on this for a couple of days now to try and get a home test to prove to myself before going somewhere that I can get 270 psi to hold and I am happy with the fittings. After Saturdays efforts I took all the fitting off and redid them with liquid PTFE instead of tape, after speaking to Ian at STW who advised that the tape can let pressure through the individual layers. Also rearranged the cocks on the gauge to try and move the leaky one from the blowdown and used some graphite yarn on the clack stems.

Filled up and pumped up and got to 300 psi with no leaks at all, after 10 mins it was still at 250 so YIPEEEEE cheers cheers All systems are go for the first test. Went to the local ME open day on Sunday to curry favour and spoke to the guy who will do the test and he said that providing I could do what I have just done he would be satisfied. Feels like another great milestone has been passed Very Happy







A few tips for those following, the simplest way to get this test done is to isolate the cylinders so as to eliminate a lot of areas that will leak. The plate is supplied by STW and I just drilled and tapped two M6 bolts to then hold a small brass plate over the reg hole to block off the input to the HP chest. The reg rod needs to stay in place to fill the holes up but a good application of PTFE square yarn seals this easily. The whistle base is just a plate with thick gasket paper under and after failing to stop the simpling valve leaking I took that off to and made a small plate to block it off. Have the LP chest cover off you'll soon see a leak if it won't seal.

Unless you have been either a: very meticulous or b; very lucky it is unlikely that your fittings will be water tight. Steam is another matter, none of mine leaked when steaming or not to an extent that I was concerned but under cold they dont seal well. Give up with the white PTFE tape and buy some liquid PTFE thread sealant, very effective and much easier than the tape. The one I have is called "Gimme the white stuff", Take all the fittings out and remake, assemble using a good dollop of this stuff, trust me it works first time. The clack stems need yarn in them to seal to the brass nut and the the balls need to be seated in the bass, simply take off the clack, open the top and then using a rod of some description give the ball a sharp tap in situ to make the seat take up the ball. Dont go too hard but as they are stainless they shouldnt dent. I used a 1/4 BSP union in the siren hole and blanked the hole in the plate (also 1/4 BSP ) which allowed me to fit the Rothenburger pump straight in.

I would be interested to know how every one else gets on especially with the sealing of the fittings. I don't think I had paid that much attention to the sealing during assembly but when I make the next engine ( Ha Ha Ha, not a chance, over my dead body.... ) I will do it better.

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Re: Pump it up!!!!!

Post  bjwlancashire on Thu 21 Jun 2012, 12:47 pm

Kev

That is good news after a lot of frustration, real progress. I have recently bought some jointing compound so I think I ill need to use this on the fittings instead of PTFE.

It's good to be a little behind still, the forum is proving invaluable again!! cheers

Brian

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Re: Pump it up!!!!!

Post  Tim Watson on Sat 23 Jun 2012, 6:12 am

Kev:
Where did you get "Gimme the white stuff" from?
Tim

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Re: Pump it up!!!!!

Post  highpressure on Sat 23 Jun 2012, 8:11 am

Hi Tim,

Local plumbers supplies end of my road, cost 7 and well worth it, much easier and more reliable than the tape. Can get similar stuff from screwfix just listed as PTFE thread sealant. Will I see you at something soon? Are you going to Wiston ( nr Steynning ) or Portland and Weymouth or Lingfield or Weald and Downland ( Singleton)? Otherwise at the GDSF or possibly Amberley or Exbury?? Question

Kev

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Finally got a ticket!!!!

Post  highpressure on Sun 15 Jul 2012, 6:13 am

Well today was the day to go to the local ME and carry out the hydraulic test. Despite going over it yesterday and getting no leaks, this morning it decided to leak in various places. Fortunately the guy at the club is a great chap who persevered with me and PTFE tape and we got it to almost sit dry at the required 360psi for 25 minutes or so and he was happy. Hasnt actually written out the ticket until the hot test is done is a few weeks but at least once I have made sure it will pass the hot test I am all leagal and above board. As soon as we have a rally to attend I hope to be there in full force!! cheers cheers So close now I can almost feel it!!!

Kev.

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Re: Pump it up!!!!!

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