Converted to combi now poor heating ??

[puuma2]

Hi, We had a gas fitter remove our old system which had hot water tank upstairs etc.. The fitter removed hot water tank and installed new combi, the problem has been going on for over a year...

1) radiators do not heat up (slightly warm)
2) Bathroom towel rail would take your hand off with the heat.
3) The radiator supply pipe and return pipe can roast you in 5 mins yet radiators do not heat.

As I understand it the radiator supply pipe (live) went straight from boiler to upstairs past towel rail then to were the old hot water heater cylinder was then round upstairs rooms then back downstairs... is it possible that when cylinder was removed that he has returned the hot feed straight back to boiler and so this would explain very hot return pipe with no evidence of hot radiators... we had a problem with the system cycling in hot water mode and vokera engineer repaired that and said system was not set up correct.. he said that the boiler was capable of heating house and I should get someone to check pipes for the heating side ... any ideas and how would I work out pipes... I have phoned a few plumbers but they want to start again... I can do a lot of self plumb so looking for advice ..

 

[Rob]

Very difficult to say without seeing. Can only imagine the HTG flow is a big loop and the return is maybe connected somewhere else...

Can you identify the old cylinder connections and where it teed off to the htg.

What sort of system did you have before..fully pumped? Motorised valves?

Could it not just be a badly sludged up/blocked system?

 

[puuma2]

The system has been drained a few times and fernox has been used to clean it inside..

the old system was a standard type boiler with hot water cylinder upstairs with pump next to it with a tri port valve, hope that helps.....

yes I can see where pipes are closed off and returned..

 

[wonderb0y]

have you told the installer about the problems?

 

[puuma2]

have you told the installer about the problems?

Yes, its over a year now but he says that's the way combi boilers are and he does not like using them due to poor performance... We kinda put up with it but I recently changed a friends radiators and realised the difference you can burn yourself off everyone of friends radiator...

One man band installer and I would rather just get it fixed that have a fight.. when he first installed he took 3 days cos it kept shutting down.. then he changed pipes at old cylinder and said at time he joined wrong pipe but then it seemed to work just poorly I never thought much about it till vokera guy made comment then friends system

 

[Agile]

It sounds as if you have had a most incompetent person to install your new boiler.

The smallest combi boiler will give enough heating for a five bedroom detached house!

Its inpossible to say what your problem is. It may be as little as needs balancing ( see FAQ ) or it may be sludged up or it may be wrongly piped.

You need a competent person who is not short of work! That may not be so easy to find.

Tony

 

[puuma2]

If system required balancing would the return pipe not be cooler rather than roasting like the supply pipe.. the water is returning very hot just not heating radiators

 

[Agile]

That may be a wrongly piped system or just an unbalanced system.

Try turning the towel rail off for a start!

Tony

 

[puuma2]

That may be a wrongly piped system or just an unbalanced system.

Try turning the towel rail off for a start!

Tony

I have put towel rail off completely before but it makes no difference to heat at any radiator, I have turned all upstair balance valves to very low and hoped for warmth but makes no difference... I turned all radiator upstairs completely off but makes no difference to radiators downstairs..

4 radiators downstairs, if I turn all radiators off in the house except two in living room we can get heat .. not amazing heat but warmer radiators... best place to get warmth is next to supply and return pipe at boiler

 

[JohnD]

If the return pipe is roasting, doesn't that suggest a bypass somewhere?

But "when he first installed he took 3 days cos it kept shutting down.. then he changed pipes at old cylinder and said at time he joined wrong pipe but then it seemed to work just poorly " suggests an error in installation.

 

[pannierstan]

I cannot believe that you have put up with this for a year! and what did it take for him to convince you that "this is how they work" crap.

I will tell you now he has got the configuration of the pipes wrong. The combi should have been connected to the central heating flow from the old 3 way valve in the airing cupboard and then to the PRIMARY return after all the other radiator and hot water cylinder returns had come back.

Is the new combi situated where the old boiler was?
If so then he will have only needed to alter a few pipes in the airing cupboard to isolate the cylinder and the header tanks. Job done.

As Tony said you have inadvertantly employed a lemon.

Was he the cheapest or cheaper quote by any chance

Stan

 

[puuma2]

If the return pipe is roasting, doesn't that suggest a bypass somewhere?

where tank was no valves exist... everything has been capped off except two 22mm pipes that have been connected together... correct me if I am wrong .. I was thinking the two 22mm pipes could be supply and return ? and the 15mm capped off could be a supply to a radiator as after the cylinder would the supply to my radiators not be 15mm obviously one of the 22mm capped off would be hot water supply to bath etc.. I have two other 22mm pipes capped off too.. where the 22mm pipe is in cupboard where old cylinder was is the last place I can burn self on pipes... this is after towel rail but before all other radiators..

 

[gas4you]

As the others on here say it is very hard to diagnose this from afar!

How old/what was the original system? he may have used the original 28mm primaries off the old boiler and the towel rail was plumbed to these. If you had gravity hot water system (pump only ran rads) before did your towel rail get hot all through summer when just hot water was on?

Another possibility was that if it is a very old system that it was a single pipe system and he didn't realise it

There may be an old anti-gravity check valve somewhere on the rad side of the system that is now blocked or the new flow is going the wrong way for it to open.

I suspect that your rads getting very slightly warm indicates a gradual convection via the return pipe.

Please reply with as much full info on your old system as poss

 

[puuma2]

pannierstan your estimation of job is correct.. the boiler is still in old boilers position, In answer to price he was not the person employed to do the job, I was suppose to be using someone else but then his previous job ran on ... so another guy turned up to get job done... cost £1500 I supplied boiler as I supply merchants with products they supplied it free..

 

[puuma2]

System is 12 years old, boiler was changed from a glow warm cause of noisy fan and I felt no point in replacing due to age of boiler... the heated towel rail is fed from under floor and the 22mm supply pipe runs in same direction so I guess heated towel rail is tee off 22mm as it would seem to make sense.. towel rail would only get warm when central heating part was on, not hot water only if that helps.

never thought much of the towel rail before just know its the warmest place in the house..