Baxi 552 BBU - burner re assembly after clean out

[jirams]

I reported on this forum last weekend my success in cleaning out 552 burner and removing lint trapped in filter. This cured a yellow burning flame - very pleased with result EXCEPT:-

I am getting a lot of expansion clicking and ticking now from what I reckon is the burner when cycling on and off. I am never sure just how much to tighten up the 2 nuts which secure the RHS end plate onto the burner outer sleeve. The sleeve sits on dished rims on the end plates and you can go on tightening up the nuts and expanding the ends of outer sleeve until it might get damaged (this version here does not have gaskets). The nuts usually are found loose on well burnt in burners. I am sure the expansion noises are coming from these nuts not being set correct??

Can anyone offer advice please?

 

[Reg Man]

Try backing them off a quater turn. Gives it, a little room to move, because it all heats up at different rates. Normally BBU's used to make ticking noise, because they are not screwed down to a flat base.

 

[Reg Man]

If your not experieced with Back Boiler units (BBU's) then here's a couple of tips, There are a few common faults to look out for. The side walls where the pipes come through should be properly sealed with suitable material (Brick and cement); the space between the chimney and flue liner should be sealed (Rock wool). ie: there shall be only 2 openings, the front chimney opening and the flue. Any other openings can cause products of combustion to get pulled through them. Also the gas and water pipes should be protected against corrosion, especially if the chimney had been used in the past for solid fuel.

 

[Billy Bob Bob]

bear in mind and regman will remember this if he thinks back.....the middle baffle on 552,s used to make the noise you describe so its not uncommon to find them missing the question is was the noise there before you started?

 

[Reg Man]

Thanks Gasman, Memories.

 

[Billy Bob Bob]

no probs Reg man, my career started out with working on nothing but 551,s 401,s and 552,s know them well they are getting less and less but if i put my money on the most populer boiler ever made it would start with Baxi Burmuda

 

[Reg Man]

Me too. Baxi Bermuda was the best. Did'nt like the old Housewarmers and A framed Parkrays.

 

[Billy Bob Bob]

oh no not the hosewarmers

 

[gasmarc]

just been to have a quick survey on one today installed in 1997 so all looked good, I always quote for 2 hours when servicing these from now on, I remember doing one of these years ago in a doctors house and she said once any of that soot gets into your lungs it never comes out

 

[Billy Bob Bob]

2 hours? you are doing it properly gasmarc i do them in 1.5-2hours anyone who can do them quicker should leave the trade

 

[gasmarc]

something I do know is if you every do a GLSC make sure you remove the fire and check it is not partially blocked as this can easily be over looked ,

 

[Reg Man]

My mum in law had a BBU on a insurance contract with a company who I shall not name, but initials were BG. They were excellant, managed to service it in 10 minutes and had a cup of tea and chat. Well, I went round serviced it myself and complained. Give them their due, the customer service was brilliant. They sent somone back a week latter to do the job again. The engineer said whats wrong, its spotless, mum in law said her son in law has been round a serviced it. Engineer had the nerve to say I hope he was CORGI registered (Back a few years).

 

[tamz]

bear in mind and regman will remember this if he thinks back.....the middle baffle on 552,s used to make the noise you describe so its not uncommon to find them missing the question is was the noise there before you started?

That is exactly what it will be. Made from a light steel that expands and contracts quickly.

 

[tamz]

My mum in law had a BBU on a insurance contract with a company who I shall not name, but initials were BG. They were excellant, managed to service it in 10 minutes and had a cup of tea and chat. Well, I went round serviced it myself and complained. Give them their due, the customer service was brilliant. They sent somone back a week latter to do the job again. The engineer said whats wrong, its spotless, mum in law said her son in law has been round a serviced it. Engineer had the nerve to say I hope he was CORGI registered (Back a few years).

The old uguage trick. They were good at that one

 

[tamz]

just been to have a quick survey on one today installed in 1997 so all looked good, I always quote for 2 hours when servicing these from now on, I remember doing one of these years ago in a doctors house and she said once any of that soot gets into your lungs it never comes out

That'll be why i put on some weight in the 80's

 

[jirams]

In the past the noise has and has not been evident after a full service - this makes me think that it related to how tight the end nuts are set on the burner - I'll try backing them off a bit as reg man suggests and report back the results.

Cheers to yis all ;0)

 

[Reg Man]

In the past the noise has and has not been evident after a full service - this makes me think that it related to how tight the end nuts are set on the burner - I'll try backing them off a bit as reg man suggests and report back the results.

Cheers to yis all ;0)

Not the nuts on the end plate of the burner its self as this has a gas seal. The bolts clamping the burne in place and tthe chamber cover.

 

[jirams]

Not the nuts on the end plate of the burner its self as this has a gas seal. The bolts clamping the burne in place and tthe chamber cover.

The burner is held down on the floor of the casing by 1 screw through the mounting bracket at the pilot jet end and it simply sits on top of the lint arrestor at the other end.

I found that the burner end plate nuts were slack again when I checked today? It is possible to get to them without taking the burner out again - there was a small gas jet burning due to gas leakage down past the nuts. I tightened the nuts up again and also put a lock nut on each.

Now there is no noise at all from the burner when cycling on-off. I reckon the best procedure is to tighten up the nuts alternately whilst re assembling the burner until its feels that it is all snugged up on the dished end plates - then let the boiler cycle several times and then retighten the nuts. The thermal cycling probably allows the burner to settle itself and then the final tighten up will hold.

All silent now.

Cheers

 

[huddster]

glad im not the only person taking 2 hrs on a back boiler, im a fairly new engineer, and seem to be hitting the 2hr mark every time even working flat out, im hoping with time i can bring this down a bit to an hour an a half, but i suppose it takes as long as it takes.

 

[gasmarc]

spot on hudder it takes as long as it takes. this is what customers or any large firms do not want to hear ,hence I am very reluctant to give a price in case something needs replacing,