central heating problem! can anyone help?

[Vinterceptor]

Got up this morning to a cold house8ree!.

Don't know if any of you peeps can point me in the right general direction:dunno::dunno:

We have a gas fired Olde world'e Glow worm galaxie back boiler (prob 30 years old) which fires the central heating and hot water system.

The programmer is set for both to come on at the same time. However, only the hot water system seems to be working correctly at the moment.

The central heating system now only works whilst the hot water is heating up.
Once the hot water is up to temp, the boiler switches off, and this is despite the room thermostat being set high enough to ensure that the boiler should still remain lit.

Any ideas? faulty programmer..... faulty room thermostat:dunno: and how best to check em?

thanks in advance for any advice vin8ree!sh1tehppns

 

[marcusfordus]

Heating system

Do you also have a motorised valve on the system ?

Clocks operates the thermostat, thermostat operates motorised valve, valve fires the boiler, wether it be heating or hot water.

If you havn't and it fires the boiler off the heating setting on the clock, then one shagged pump.

If it doesn't fire the boiler off the heating from the clock it's a clock problem 80% or a stat issue 10% the rest could be wiring issues.

 

[Vinterceptor]

Do you also have a motorised valve on the system ?

Clocks operates the thermostat, thermostat operates motorised valve, valve fires the boiler, wether it be heating or hot water.

If you havn't and it fires the boiler off the heating setting on the clock, then one shagged pump.

If it doesn't fire the boiler off the heating from the clock it's a clock problem 80% or a stat issue 10% the rest could be wiring issues.

___________________________________________________

Yes cheers, it has got a motorised valve hidden behind some pannelling, will take the covers off later and see if that's working as it should.

Anyway will check it out for owt obvioius

 

[andyBeaker]

First thoughts are yes if motorised valve fitted it is not working, There should be a manual facility on the valve to move it and with a bit of luck this might unstick it. However, if the motor has gone, you can probably just change the electrics - B&Q do a universal replacement for about ?18 which will probably do the job.

8ree!good luck

 

[stormer]

First thoughts are yes if motorised valve fitted it is not working, There should be a manual facility on the valve to move it and with a bit of luck this might unstick it. However, if the motor has gone, you can probably just change the electrics - B&Q do a universal replacement for about ?18 which will probably do the job.

8ree!good luck

I managed to buy a new top half for mine a Honeywell.:yo: so didn't need to break into the system.

 

[jono49]

Synchronous motor

You can get the synchronous motor seperate....Not a big job to replace Available at City Plumbing and the likes!!!

 

[Artemis]

Historically, out boiler packs up around Christmas. Out of the nine years we've lived here the last 2, since we found a decent heating engineer, we've been lucky. Everybody please keep their fingers crossed for third time lucky this year.

 

[andyBeaker]

As for checking the room thermostat, if you turn it right up (or right down) you should hear a very loud click as it swithches on (or off). If it is clicking it should be fine.

Fiver says the motorised valve has gone phut though; not that uncommon.

 

[Vinterceptor]

Strangely

Since I first mentioned the heating prob yesterday morning, it has gone through two cycles and worked perfekly:bow::bow:. It has come on OK this morning too and when I turn the thermostat dial it switches the boiler off or on depending on which way I'm turning the dial... as it should.

However, yesterday morning when I turned the dial you could hear it click loudly as it passed the point corresponding to room temperature. But it did not fire the boiler.

The next time it doesn't work correctly I will check that the motorised valve has turned fully into position.

thanks for the sugestions folks

 

[andyBeaker]

Since I first mentioned the heating prob yesterday morning, it has gone through two cycles and worked perfekly:bow::bow:. It has come on OK this morning too and when I turn the thermostat dial it switches the boiler off or on depending on which way I'm turning the dial... as it should.

However, yesterday morning when I turned the dial you could hear it click loudly as it passed the point corresponding to room temperature. But it did not fire the boiler.

The next time it doesn't work correctly I will check that the motorised valve has turned fully into position.

thanks for the sugestions folks

Hmmm. That doesn't sound like a sticky valve. If you have a three port valve the water will always flow somewhere so the boiler should fire. This would explain the initial description of the 'wrong' part of the system heating up.

If you have a two port valve that is stuck the circuit will be blocked but even then I would expect the boiler to fire for a short time until the 'trapped' water reached a hot enough temperature for the boiler to turn itself off. However, some boilers do incorporate a flow switch so if the water is not flowing (as in a stuck valve) this would prevent boiler firing.

If the second description continues it is sounding like an electrical issue somewhere. After 30+ years maybe not too much of a surprise?

However, even though the room thermostat is clicking it might just possibly still not be working properly; perhaps a first step could be to either replace with a cheap job to eliminate this - you can short the wires as well if you know what you are doing - if there are only two wires to start join them together to close the circuit and see what happens. If more than two wires I would leave alone!! If you go for a replacement, I would thoroughly recommend getting a programmable thermostat to allow different temperatures to be programmed for each day - normally up to six different per day. Remote control portable thermostats are now available that look pretty handy - might upgrade mine as I do like th toys!!

Could also be the programmer - particularly if it is one of the old style jobs with manual sliders - they do wear out eventually. Again this can be checked by removing the programmer and shorting the circuits but you really need to know what you are doing here. A certain amount of checking can be done by moving the programme to '24 hours' but again the safest way to eliminate is to replace if you do not have the knowledge to short the circuits.

Up to you, normal health warning applies, may contain nuts etc....

 

[andyBeaker]

If posting again, please ;

• advise if hot water system is pumped or gravity fed i.e. doers pump run to feed hot water circuit or does the water circulate by gravity i.e. hot water rising only
• how many pipes go to the motorised valve - will be either one in and two out, or one in and one out

in the meantime........8ree!

 

[robsbird]

9 out of 10 times it would be gravity on a back boiler and it would be a two port valve

only opening when the heating was called for............

 

[marcusfordus]

Not always

9 out of 10 times it would be gravity on a back boiler and it would be a two port valve

only opening when the heating was called for............

There are loads of Y-plans out there with a backboiler and a 3-port.

If we knew how the boiler switched off when the water was up to temperture ( cylinder stat or internal boiler stat ) then we would have a fighting chance h1d1ng2

 

[andyBeaker]

I really hate it when someone posts up an interesting problem that I might actually be able to help with.........and then goes quiet!!

p0pc0rn41b

 

[Vinterceptor]

I really hate it when someone posts up an interesting problem that I might actually be able to help with.........and then goes quiet!!

p0pc0rn41b

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Didn't want to tempt fate...... as it's still working perfekly :bow: (will have to keep my fingers crossed that it carries on that way now).

Anyway here's a bit more info about the system.

Glow worm gas fired back boiler:

Pump: which circulates heated water through a 3 position motorised valve to the radiators and/or heating coil in the hot water cylinder.

I've removed the pannelling in readiness to see instantly what it does or doesn't do, the next time it throws a wobbler. Incidentally it's got a digital programmer and the room thermostat just has 2 wires going into it.

heres a photo of the valve

 

[Vinterceptor]

There are loads of Y-plans out there with a backboiler and a 3-port.

If we knew how the boiler switched off when the water was up to temperture ( cylinder stat or internal boiler stat ) then we would have a fighting chance h1d1ng2

__________________________________________

Oop's the last couple of posts seem to have slipped under the radar.

It has a cylinder stat for the hot water if that's what ya mean? and there's also a room thermostat too for the rads.


At no time has the hot water supply failed. The only time the system failed was on the heating side (radiators) the other day. After the hot water (in the cylinder) had reached the set temperature the boiler switched off even though the room thermostat was still set way higher than the actual room temp:dunno::dunno:

But it has been running OK since then:dunno::dunno:

 

[marcusfordus]

Two wire thermostat

Does your room thermostat have two wires or a cable with two cores in it ?

90% of stats like that need a 3-core, live in, live out and a neutral. Lots dodgy electricians dont wire them correctly, but you can get a proper two wire stat that doesn't need a neutral. You should know how accurate the thing is if it's been in a while, if it takes ages to switch itself on or off then the neutrals a missing. Give us a shout if you need a new stat, or a clock come to think of it !
Have a warm Christmas :yo:

 

[bmwdumptruck]

There's been a lot of conflicting and/or confusing advice given here. As an experienced heating engineer I'd say swap the synchron motor in the valve for a new one. They only cost ?10-15 and are dead easy to change. Kill the power, snip two wires and reconnect using the crimps that are usually in the kit. (be carefull when stripping the valves wires back, it can be easy to pull them out of the valve, and then you'd need a new valve!!)

Assuming the wiring thats there has been in and working until recently, then it won't be that, whether its wired to the book, or not.

If the HW has always been ok, the pumps ok. When the system is on for just HW the valve does nothing. Its normally open to the cylinder and therefore sits idle. The boiler and pump are energised by the cylinder stat only.

When the CH is added the valve opens to the rads and cyl, or just the rads. Chances are the motor is on its way out, hence I'd just change it for what it costs.

Hope this helps you.

 

[andyBeaker]

There's been a lot of conflicting and/or confusing advice given here.

where?:dunno:

 

[andyBeaker]

There's been a lot of conflicting and/or confusing advice given here.

where?:dunno:

How do you know if we aren't all 'qualified heating engineers'?

h1d1ng2