baxi bermuda 551 - no heat to the radiators help please

[bludclot]

we have a baxi bermuda back boiler and are under orders to have the central heating working for a family christmas visit. (it doesn't worry us too much, we put the fire on when cold.) the heating hasn't been working for the last 2 winters.

so towards heat this week i drained the radiators and flushed them through on the driveway one by one. i also fitted a new pump which i have since confirmed is working (it has power, it whines quietly and when the central copper cap is removed the spindle is visibly spinning.) but there's still no heat to the radiators.

the room thermostat in the hallway clicks as it should and when the heating is on turning the thermostat up causes the boiler to light. the boiler also lights when the heating is turned on but only ever stays lit for a minute or so then switches back off. flames look a healthy blue.

the right hand copper tube to the first two radiator valves in line from the boiler do get warm (but only warm) when the heating is switched on for 10 minutes or more. both valves are thermostatic and both are open and letting water by into the rads.

there's 4 tubes running vertically to the side of the chimney breast, 2 22s and 2 28s. i've figured that the 28s go to the cylinder as one 22 has the pump in line (flow?) and the other has a brass lump in line (return, non-return valve?) the 28mm pipes get properly hot, the 22s only warm to the touch, even when the heating is left on.

we have lovely hot water from the taps, no problem there.

any suggestions as to what's stopping the heating working please? there's no external 3-way valve fitted, is there a valve in the boiler that's stuck perhaps? other thoughts i've had are that maybe the pump is not man enough to get the water moving (although kitchen rad vibrates as though there's a flow through it) or that the non-return valve might be stuck shut? other than this i am very stuck. we are a low income household (despite us both working, we take nothing from the state either through pride) and do not have any real money to throw at this problem.

help and suggestions very appreciated.

 

[craig51]

Sounds liek you might have gravity hot water and pumped ch, so the simpliest of systems.

Either the pump is goosed - You changed and checked this
The pump valves are closed - did you reopen these?
Did yu put the pump on the right way, if not the non-retunr valve will be stopping flow
Does the pipe coming from boiler to pump get hot?
Does the boiler fire up when heating demand is made?

Or, you have a blockage somewhere, are all rads open?

 

[expertgasman]

Either pump is on wrong way - it is normally on the return, or the NRV valve is stuck or full of crud. It is there to stop gravity circulation when water on.

The puzzle is why the burner only fires for a minute. Is this when the HW is already up to temperature?

 

[bludclot]

the boiler only fires for a minute when the water is up to temperature, yes. when heating is then asked for the boiler fires straight away but only runs for a minute again.

both valves either side of the pump are open and were replaced when the pump went in as they were both partially seized (exceedingly stiff in operation.)

the pipe from the boiler to the bottom of the pump doesn't seem to get very hot, certainly not as hot as the 28s to the cylinder.

the pump is located near the ground floor so i fitted it with the flow arrow pointing upwards. the nrv is just a couple of inches higher than the top of the pump. (not in the same tube though!) it is very straight forward for me to isloate, remove, invert and re-fit the pump, but i think tomorrow i will drain the rads and remove the nrv and take it to my local merchants and match it and re-fit it first. i will re-post having tried these two things and let you know...

 

[OwainDIYer]

if the boiler cuts out after a minute then the heat is not leaving the boiler. This points to some problem with the radiator circulation, whether it's a valve, pump, or maybe an airlock?

 

[Agile]

I would say that the pump is not pumping at all.

On this boiler it still works whichever way the pump is connected. Its just the boiler stat does not work so well.

Gravity HW will still work OK though with no pump action.

OP, I find your forum name rather rude in Jamaican slang!

Tony

 

[bludclot]

no rudeness intended. taken from drum'n'bass / jungle influences. i use this handle on other forums and nobody else has found it rude.

in detail - taken from the ed rush and nico tune 'bludclot artattack' on no u turn records. as far as i am aware the jamaican insult is actually 'bambaclat' which roughly translates as blood clot. i am (as ever) willing to be further educated on this however.

i'm draining the radiators right now in order to change the nrv and/or invert the pump and will report back.

 

[bludclot]

well what can i say? i don't know how to express my thanks to you enough.

a huge big thank you to all that replied.

i drained the rads and removed the nrv - i gave it a good wash out in the kitchen sink and verified that it worked. i also marked it before it came off - and then knew that it was allowing water upwards and not down - haha! so the pump was indeed the wrong way round. i inverted the pump, re-filled and bled and bingo! it all works a treat.

this is the quote that really clarified it for me:

Either pump is on wrong way - it is normally on the return, or the NRV valve is stuck or full of crud. It is there to stop gravity circulation when water on.

so my first experience of this forum has been very good indeed.

i fit kitchens and bathrooms for a living, i'm part p qualified, can plaster and tile - so fully intend to stick around for a while and see if i can help anybody else by way of return.

many many thanks again.

 

[Agile]

But how did the pump come to be wrongly fitted?

I am also surprised that you have apparently lived like that for TWO years!

Urban dictionary:

"bambaclat "

A rag that women used in the ghetto instead of tampons.
This rag was also known as the bumbaclot... a.k.a. blood clot
This word could be used in a state of surprise or anger, but it is mainly used to insult.

1. What da bambaclat is dis?! I asked for a coke!
2. Yo' mama is a bambaclat
etc.

I was once called that by a customer when I had not been to fix her boiler for a couple of days! But then I know her well.

Tony

 

[bludclot]

christmas before last i stripped out the second bedroom to re-plaster and decorate it - usual thing, paper away from walls, skirting boards off etc. seeing as the plumber that first fixed this house didn't have a spirit level or an eye for a straight line i'm taking each radiator off, lifting the floor, cutting the pipes back and re-plumbing the tails straight! anyways, when i finished the room i re-filled the rads and the heating didn't work. i diagnosed the pump not working at the time and took it off (without noting orientation) and took it to my local merchants to match it. when i got home i guessed that it pumped upwards and fitted it. the central heating didn't work. it has stayed that way until this week when i tried to run it again and (yes you guessed) diagnosed that the pump didn't work, hence my initial post here.

i have lived a fair amount of my adult life without central heating - it doesn't bother me or missus. neither of us are sit in front the 'tele types - we would rather be active so heat is not needed. in fact when i walk into a centrally heated house that's set to anything above about 18 i find it rather uncomfotable - oppresive is the best word i can find to describe it. at work i always have the window(s) open.

frankly i feel a bit sorry for anyone that has to have central heating on to live or be comfortable - how far removed from nature do you want to be?

as regards the name (bludclot) i was unaware that it could be considered rude - espcially in another language and then even further away - in that language slang! amazing..... let's hope nobody is offended hey.

btw - since the heating was fixed it hasn't been turned on.... it just doesn't occur to us.