positive pressure boiler

[jimmyjj]

hi. some advice on positive pressure boilers pls

just wondering what you guys do if ur doing a landlords or service on say a neataheat 10/16 . the casing is always against the wall so you cant test with ldf if the seal is correct so im reluctant to remove casing as long as co reading and flame pic is ok. since i cant test the case integrity due to insufficient side clearences around boiler i simply put down NCS . is this correct. nearly every positive pressure case ithat ive removed has failed to seal back correctly thus having to cap off appliance. a corgi inspector told me to temporarily seal with silicone!! surely not??

 

[AlanE]

This should really be in the combustion chamber mods.

 

[gas4you]

If you are not removing the case, how are you servicing/inspecting it?

I've never had one leak after a service yet. I was at a 10/16 Friday and the case seal was not hard up against the wall, it is fitted into the sealing strip around the back of the boiler rear plate

 

[namsag]

Who taught you to use ldf , i take it that is leak detection fluid as this is not the correct method

 

[scatmanjohn]

so you cant test with ldf if the seal is correct

As namsag has said, what are you doing testing case seals with LDF.

 

[jimmyjj]

by putting ldf around casing bubbles will form telling u if poc are leaking. every single neatheat 10/16 that ive applied ldf to has had hugh bubbles emerging . usually at the edges.ive capped of at least 6 of these beats last month .

 

[namsag]

Was not the question , WHO told you to check it this way , anybody or did you decide it yourself.

 

[jimmyjj]

how is a lighted taper any better then using LDF?. damaged seal= fan blowing into lDf solution thus causing bubbles to form.exactly same effect as when u dip a bubble stick into fairy liquid and then blow in to the stick causing a bubble. 2 corgi inspectors have recommended this.

 

[Gasguru]

...... 2 corgi inspectors have recommended this.

Well I suggest you go and tell them to read their own TSB on case seal testing. No positive pressure boiler will seal 100%..the manufacturers never intended they did and the testing standards at the time allowed for this. Using LDF is bound to fail every casing seal apart from being an electrical hazard.

The recomended test method is to use smoke/flame. Very rarely I have had to replace the casing seal...leakage is sometimes detected at the top corners. Often just due to insufficient pull down of the casing screws which can be resolved with a little copperease on the threads.

Have a look at TSB127

Personally I use the smoke pen; it is very effective and also useful for testing modern fully pre-mixed burners (that are obviously positive pressure after the fan).

Untitled

• Gasguru
• 8 Jun 2008
• 2

Untitled

• Gasguru
• 8 Jun 2008
• 2

 

[petit_pablo]

Ive never heard or seen anyone test a case seal with LDF!

I use simple, common safety matches as do most people i would imagine

 

[jimmyjj]

interesting. smoke pens from plumb center?? i cant believe seals were not intended to be 100 percent effective thats scary stuff. nothing should be coming out of a positive pressure boiler as far as im am concerned. going to refuse any service or landlord checks on these. for the sake of a couple hundred quid lost every year its just not worth it.too many people have been poisoned by these turds. thansk for the smoke pen . and pics very informative

 

[nickso]

why worry about it?

do your tests properly and make sure the performance test is low and thats it, theres no way a case is going to 100% airtight on any boiler.

 

[Gasguru]

interesting. smoke pens from plumb center?? i cant believe seals were not intended to be 100 percent effective thats scary stuff. nothing should be coming out of a positive pressure boiler as far as im am concerned. going to refuse any service or landlord checks on these. for the sake of a couple hundred quid lost every year its just not worth it.too many people have been poisoned by these turds. thansk for the smoke pen . and pics very informative

Smoke pens are available from BES and were introduced to the market after the original Advantica report and corgi TSB. Obviously a smoke pen is considerably safer to use than a lit match or lighter especially since combustable surfaces are often in the vicinity of the boiler casing.

Read the report and have a look at the old standards these boilers complied with....a 100% casing seal was not intended.

You won't be very popular if you start disconnecting/refusing to attend positive pressure boilers for no good reason. You are also scaremongering. Are you going to refuse to touch gas fires?, many (most DFE/ILFE/OLFE) are purposely designed to produce carbon monoxide. Casing seals are a low cost part (I've only ever fitted a few to Netaheats) and hence never had to condemn a Netaheat due to casing seal failure.

You will loose more than a couple of hundred quid...there are a significant number of positive pressure boilers out there...the Netaheat Profile only ceased production a few years ago. Very few people have been poisoned...nearly all due to poor maintainence by ill informed/shoddy installers. I will guarantee that some of the latest fully pre-mixed boilers will prove to have a far worse safety record than the old Netaheats. The recent twin flue fiasco and Vaillant recalls are sufficient evidence already; Powermaxs are another shineing example.

Further reading Advantica report

Note the incorrect image in the file....the lower controls cover should always be removed and the wiring panel hinged down to ensure the smoke pen can be fully exposed to the lower casing sealing.

 

[jimmyjj]

thats great information thanks.wheres the best place to pick up a variety of seals? i tend to use some foam wrapped in silicone as a stop gap for small gaps in casing but would much prefer a delection of case seals.

just one more thing regarding these boilers. invariably the boiler is in the corner up against the wall or squeezed between two cupboards so you cant possibly test the sides of the boilers for leakage. thats really my point, u can test the corners but not the sides because some installer hasnt left sufficient clearences around the boiler

i do refuse posistive boilers and gas fires unless the landlord has a co alarm already installed. this usually weeds out the crap landlords and if the whine about it , its goodbye. these types are unlikely to have it checkjed before, have been warned countless times , too mean to install an alarm let alone a new boiler. im semi self employed and make a very good living out of landlords and repairs so refusing hasnt effectedn me at all. also at least 30 percent of fires
i used to attend were ar or id due to bad install's, bad landlords and moron tenants not listening to me and then landlords not paying up because i wont go up on roofs to check their chimney for a nest!!! really not worth it mate and i definitley havent suffered because of it. thanks again for the info very informative. regards

 

[namsag]

lLooking at the advantica report. The incident with the netaheat back in 91 when the case was left off. Mate was involved with this and the guy left the case off because that is the only way the boiler would stay lit. Nearly killed 2/3 people .
Boiler was in a bathroom and quickly took all air out the room and then reburnt the products so CO level rose at alarming rate . Don`t think the guy even got a fine . He is still out there working and is still no better.
Luckily enough in our area most guys are ok .and those that aren`t stay away from fire installs etc and leave them to guys that know . Some of the shi#e you guys in cities must have to deal with would certainly keep you on edge.