Central Heating

[the_lone_wolf]

The law of sod appears to have struck the house here...

Central heating has gone a bit wibble, the thermostat clicks when you turn it up but the pump doesn't kick in and get the water flowing...

The odd thing is that the heating comes on occasionally, but doesn't seem to be in any kind of pattern and it's not keeping the house as warm as it would normally?

Any ideas? Engineer was £75 just to get to the front door, and I even offered to provide my own lube...:-dd

[maviczap]

£75 is about the norm, I pay about £65 for them to come out and service my boiler. About the same for an emergency call out

Could be a miriad of things, so it would help to know what kind of CH system you have.

Combi boiler, hot water tank

My boiler developed a fault and several engineers came out to try and fix it, but the fault kept coming back, same as before. Then they sent out their top guy who knew what the problem was almost immediately. And he was the yougest of the lot, one of the others was an ex British Gas employee with loads of experience, but he couldn't solve the fault, as it was in the electronics

Sometimes a local independant guy in the yellow pages can be cheaper, but depends how good they are. Make sure they're CORGI registered

[the_lone_wolf]

Could be a miriad of things, so it would help to know what kind of CH system you have.

Boiler downstairs, hot water tank upstairs

Sorry, don't know much about plumbing:-$

[Bluefish]

i'm going for zone valve/three port valve without knowing any details.
as said combi or system boiler what make model?

[maviczap]

Not a combi system then :p

There is elec to the thermostat then, so then is the bolier igniting when the themo is clicked & have you got hot water in the tank?

If you have hot water then the boiler looks to be working ok:p

Then I'd suspect the pump next, you can hear & feel it working. So long as you know what it looks like:p

[Bluefish]

ok not combi, when you turn the stat up with heating turned on, does the pump run is there 240volts to it, if you can hear the pump humming get a large flathead scredriver undo the silver screw in middle of the pump put screwdriver in and turn the driver to get the pump going again, this will only work if there is power to the pump, if no power suspect the zone valve, see the little lever on the side of the valve push it open all the way quickly does it make the contacts, if it does you need new valve valve head or motor for inside the head, all depending on what type of valve it is. hth.

[Scoobs]

Water pressure?

[no_akira]

Have you bleed the uppermost radiator in the house, you could find over the summer CH break air has built up in the system. It normally rises to the highest radiator in the house.

[DarrenSV650S]

Have you flicked the kill switch?

[the_lone_wolf]

Wow! Thanks for the enthusiastic response folks:thumleft:

No shortage of hot water, it went wiggy yesterday morning and we've had showers etc since with no interruption

@Scoobs - not sure what you mean? Both cold and hot water seem to be flowing from the taps as well as before, just the heating that doesn't kick in when you up the thermostat, imagine you're explaining it to a small child, or possibly an intelligent dog, and you'll get the level right...;)

@maviczap - The boiler didn't used to respond to the thermostat switching before and doesn't now, there is hot water in the tank, but the pump doesn't appear to be functioning

@bluefishman - as above, pump doesn't click on or appear to be activated when the thermostat switches. How would I go about seeing if it's getting 240V without electrocuting myself? This is the pump itself:

http://i488.photobucket.com/albums/rr243/ktm_wolf/misc/DSCF8392.jpg

http://i488.photobucket.com/albums/rr243/ktm_wolf/misc/DSCF8392.jpg

The pump does seem to work, after we run hot water from a tap, the pump activates a minute or two afterwards and the radiators in the house heat up but after a while it stops...

I assume the "zone valve" is the black plastic lever ~1" long on the side of the pump?

@no_akira - There are five radiators on the 1st floor at the same height, if the pump activates as above when the hot water runs and the radiators all heat up it sounds more like a problem with the thermostat or pump no?

[Stuuk1]

Have you flicked the kill switch?


Yea, check there is a spark at the plugs too. Just hold it down to the bodywork...

[Jabba]

Stuck valve?

Our system went TU earlier this year. Got a fixed-price repair from BG which seems good value at the time.

Shame that the flue had gone so the boiler needed mending anyway :-(

Got a nice new, quiet, efficient condensing combi now..... miles better than the old Worcester/Bosch 240.

[Bluefish]

hi, on the side of the pump the black part, you undo the cover and with a multimeter see if there is 240v when you have the heating on if you have voltage but pump not running, pump=fubar. if you don't have 240 then then it is possibly the zone valve which is the silver box on the right of your picture, is will say honeywell on the cover.

[fizzwheel]

Have you tried turning it off and on again ?

[the_lone_wolf]

Update:

Heating's been on for 10-15m now and all the upstairs rads are searing hot, the downstairs rads aren't, of the three one is hot all the way through, the other two (the bigger two) are warm at the top but almost cold at the bottom, thinking it could be an airlock somewhere perhaps? Bleeding attempts result in inconsistent pressure from the two bigger rads

My google-fu tells me that black switch on the pump is just a speed setting, and my investigative wiggling would agree, the pump also fails to respond to the thermostat when it would normally switch off as well, meaning the pump is just running constantly now...

[Bluefish]

sounds like you have an airlock stopping the down rads getting hot, turn off the upstairs ones to force the water to downstairs, alternate the pump speed between 1 and 3

[maviczap]

sounds like you have an airlock stopping the down rads getting hot, turn off the upstairs ones to force the water to downstairs, alternate the pump speed between 1 and 3

+1

[the_lone_wolf]

hi, on the side of the pump the black part, you undo the cover and with a multimeter see if there is 240v when you have the heating on if you have voltage but pump not running, pump=fubar. if you don't have 240 then then it is possibly the zone valve which is the silver box on the right of your picture, is will say honeywell on the cover.

Thanks for that:thumleft:

The pump is running, it's hot and humming away so I assume there's power coming to it? The speed switch appears to be working fine as the pump noise lessens as you'd expect on the lower settings. I can check the voltage if you like, I assume it's safe to do so while the pump is active?

The problem appears to be that the pump doesn't respond to the imput from the thermostat, when it clicks ON the pump doesn't switch on and when it clicks OFF the pump doesn't stop


Oh, and LOL @ fizz:p:mrgreen:



EDIT: will try doing what you guys suggest in posts #16 &17 and report back:cool:

[Bluefish]

intermittently tun the programmer ie htg and hw both off to allow air to rise up the vent pipe, if there are vent in the cylander cupboard to clear any air the ones that you vent with a radiator vent key then keep bleeding these, if it is airlocked there is no set way to clear it, everybody does there own way, one of our guys been in the job 30years swears by washing up liquid in the system to beak down the air.

[Bluefish]

if the pump is running there is no need to check the voltage, so you can leave that alone.

[Bluefish]

you say the pump don't come on but it must come on for it not to go off, some systems have what you call pump overrun, that when the boiler has gone off the pump still runs for about 5mins to allow the boiler to cool down to stop it overheating. when you say the pump doesn't come on do you mean the boiler fires up but the pump the pump doesn't run, this would cause the boiler to overheat cue banging and crashing noise at the boiler.

[Sid Squid]

Switches in three port valve.

[the_lone_wolf]

you say the pump don't come on but it must come on for it not to go off, some systems have what you call pump overrun, that when the boiler has gone off the pump still runs for about 5mins to allow the boiler to cool down to stop it overheating. when you say the pump doesn't come on do you mean the boiler fires up but the pump the pump doesn't run, this would cause the boiler to overheat cue banging and crashing noise at the boiler.Let me clarify:

The pump doesn't come on when you raise the thermostat temperature above the "click" threshold

The pump does come on if you run a hot tap for a couple of minutes, which seems very odd???

The pump also doesn't switch off when you lower the thermostat below the "click" - you have to wait ~15 minutes and it stops by itself

This is everything in the airing cupboard related to the CH system:

http://i488.photobucket.com/albums/rr243/ktm_wolf/misc/DSCF8394.jpg

Can't spot anything that looks like a radiator key to bleed the system myself??


Just got your PM, will give you a call in a short while:thumleft:

[Sid Squid]

Stuff about his heating

Which is why I said:

Switches in three port valve.

The green box on the piping above the pump is the three port valve, (sometimes called a mid-position valve). The 'stats operate the valve to direct the water flow where it's required - (either through the heating coil in the cylinder and/or through the radiators), and also as the valve changes position it operates switches, these switches are the ones that turn the heating system on and off, (turn on and off the boiler/pump).

The pump and boiler are probably working just fine, but the microswitch in the valve that switches the pump/boiler on when the valve is in the heating position isn't being triggered. It probably wants the little strip of metal that clicks it bending a bit.
In these circumstances it will often work right when the manual lever is used, does it?

PS. The tee above the pump with the brass end on it is a bleed valve.

[Bluefish]

no, you need to undo the little caps on top offr the pipework, the brass cap with a pair of grips do not take it all the way off, just loosen it and see if any air comes out, tighten up if water comes out, the red cap is on what we call an auto air vent but if it is fully done up will not allow air to escape, so loosen if tight, if water comes out then tighten again.
pump goes off after 15mins that is ok that is the pump overrun feature, so your only problem now is pump not coming on straight away which as i said befor could be the motor in the, cancel fixed by telephone

[the_lone_wolf]

Sid, sorry, would have got back to you sooner but was speaking with bluefishman over the blower, you were both on the right track with the three port valve, the selection lever was a bit sticky but some frantic fingering appears to have solved the problem and we're back on track

BIG thanks to all who offered advice, beer tokens redeemable at the next AR:cool:

[maviczap]

no, you need to undo the little caps on top offr the pipework, the brass cap with a pair of grips do not take it all the way off, just loosen it and see if any air comes out, tighten up if water comes out, the red cap is on what we call an auto air vent but if it is fully done up will not allow air to escape, so loosen if tight, if water comes out then tighten again.
pump goes off after 15mins that is ok that is the pump overrun feature, so your only problem now is pump not coming on straight away which as i said befor could be the motor in the, cancel fixed by telephone

I hope you've noted all the time on your job sheet bluefish man, its going to be a big invoice at the AR I think :p

[Bluefish]

yes sure did, even phoned him back at my expence, time and a half, plus costs for heating lighting bills, and other office expences etc, lol. ;)

[dirtydog]

Sometimes a local independant guy in the yellow pages can be cheaper, but depends how good they are. Make sure they're CORGI registered

I'd rather they were Gas Safe certified as Corgi isn't what you need anymore, but if they're not doing anything with the gas any competent engineer/plumber will do.

[johnnyrod]

is 60C a bit hot for hot water? I'm looking at the knob on the tank. If you need mroe than a little cold water to make it bearable then I guess that's wasting heat?

Glad you got it fixed though!

[RichT]

Anyone know anything about electric boiler systems? We've got a problem with ours atm. Everything seems to be running, fan, pump etc but the system keeps tripping after 30s or so.

It's a Trianco jobby similar to the attached.

I've a seperate emersion on the tank which is giving us hot water but the heating is a different matter.

[dirtydog]

is 60C a bit hot for hot water? I'm looking at the knob on the tank. If you need mroe than a little cold water to make it bearable then I guess that's wasting heat?


I'd rather waste a bit of heat/energy than get legionaires (sp?) disease

[Bluefish]

is 60C a bit hot for hot water? I'm looking at the knob on the tank. If you need mroe than a little cold water to make it bearable then I guess that's wasting heat?

Glad you got it fixed though!

no 60deg c is what it should be, but it could be hotter than what it is set at if the stat is knackerd, if you think the water is too hot ie boiling/burning then turn the stat down. would be good to test the temperature of the hot water to see actual temp. but as said needs to be 60 to stop diseases.

[Bluefish]

Anyone know anything about electric boiler systems? We've got a problem with ours atm. Everything seems to be running, fan, pump etc but the system keeps tripping after 30s or so.

It's a Trianco jobby similar to the attached.

I've a seperate emersion on the tank which is giving us hot water but the heating is a different matter.


don't really work on them but it could be the stat is faulty causing it to trip, could be other things, does it have two pumps? if so are both working, are the stats set to the correct temp? edit could you get some smaller pics, lol.

[RichT]

Well I still have to get the thing looked at... Fortunately being a flat it doesn't get too cold and we've hot water.

BFM - I'll take a look and get some better pic's. I'm a complete noob in this respect.