help - heat not working

We have a gas combi-boiler.  Our hot water sort of works - it cycles from cold to scalding, with the temperature control dial only affecting the length of the scalding part of the cycle.  In addition, you have to have the tap open full to get the boiler to kick in.

We did get our heat to come on last night, but that was the first and only time.  And it's no longer working.  We have a timer box, but no thermostat.  When the heat part of the boiler is switched on and the timer box is set to on the pump runs in the boiler, but the burners don't come on.

Ant idea what the problem might be?  The only thing I can possibly think is that the system might need topping up with water.  I'd really rather figure this out ourselves, but if we can't the landlords are getting a call tomorrow.

I think the landlord should be getting a call right now!

No thermostat? sounds a bit iffy to me..

Taps have to be turned fully on to get the burner to kick in? ..  sounds a bit iffy to me

Heating pump works but burners dont kick in? ..  sounds a bit iffy to me

Was the system working correctly previously? if so, it sounds as though this setup has 'worked' but to a limited efficiency level (no thermostat etc)

if not, I suspect dodgy or incorrect installation - which in worst case, could be 'dangerous'

Call the landlords right now and get them to call out a plumber now to fix the issue or at least, diagnose the issue. If i was a tenant, that's what I'd do seeing as this isn't a 'small' issue it's quite a subtantial issue.

I'm not a central heating expert, Paul probably knows more, but I don't like the sound of what yer describing..

Good luck! DtM! West London & Slough UK!

I think we figured out why it worked last night - I was washing dishes so the boiler was on, therefore it was heating all the water, including the CH water that was being pumped.

I think Dennis might be a little too suspicious...

I assume by no thermostat the OP means that there is no room temperature thermostat, the heating is either on or off.  This is not the best set-up but is relatively common.  There should be some water temp control on the boiler hidden behind a panel somewhere, I'd be a bit worried if my boiler didn't have one of these.

I'm no boiler expert but the way combis work is they heat the water "on demand" using a flow sensor to detect open taps by water flow through the boiler.

The fact you need to fully open the tap sounds like this could be the issue.  It shouldn't be a big deal, these things only have a limited lifespan.

I'd get the landlord out ASAP.

A similar thing recently happened to a friend of mine when he moved into a new flat, and it turned out that the previous tenants had adjusted the thermostat on the boiler, which is usually behind the cover.  Have you recently moved in?  If so, this might be a possibility.  If not, it may be that there is a problem with the thermostat.  Either way, this is something that your landlord should deal with. Call him now!!!


Vicky

Hi

Yep, maybe a little too suspicious, but from my experiences at home with boilers and installations etc, what the OP is describing is a little alarming. For instance, my aunty has a gas powered combi boiler, and although you do have to turn the taps on a little 'more' to get the boiler to kick in, it's never been that the taps have to be fully open - that to me suggests pressure issues.

Having no thermostat in a domestic environment suggest corner cutting when the system was installed. Using a 'heat level' control on the boiler (which isnt really a thermostat thats used for room temperature control) is a very rudimentary control system. Usually on combi boilers, it controls how much heat energy will be transferred to the radiators, so using that to control room temperatures is very innacurate.

Again I'm not an expert, but the above is why I'm skeptical the OP's situation is 'correct' as such, maybe it really is a normal or known way of doing things - I just havent come across it or heard of it before, and I've spoken to ALOT of tradespeople as well as friends who are in the industry too.

cheers! DtM! West London & Slough UK!

Is it by any chance a Potterton? We had a similar problem and there was something faulty in the circuit board. It was even brought up on that tv show, Watchdog. Eventually Potterton started refunding people for the repairs.

Is it by any chance a Potterton? We had a similar problem and there was something faulty in the circuit board. It was even brought up on that tv show, Watchdog. Eventually Potterton started refunding people for the repairs.

Oh brother! We have a Potterton!

Hi Dennis,

I wasn't suggesting that the boiler temp control is a substitute for a room thermostat, I was just making sure I was talking about the same thing as the OP.

You are correct that having to fully open the tap is not normal, my point was that it sound to me more like a simple faulty part that needs to be replaced rather than dangerous cowboy installation which you seemed to assume.

Apologies if I mis-understood the point you were making.

Sorry I'm a little late jumping in here, but I've only just noticed the thread.

Trying to diagnose problems on these systems from a distance can be tricky, because there are different ways they can be configured.   The combination of faults described is pointing toward either flow problems or a controller fault though, which is probably going to be outside your DIY scope of tracing and repairing.  The control circuits on some of the modern combi units can be fairly complex to regulate everything.   

The no-heat fault could be caused by low pressure in the close part of the system.  Some combi units have a manual valve which you need to open from time to time to keep the pressure up -- There's normally a gauge behind the front panel for you to check.  Do you have the user's manual?  It should explain how to check that.

As for the issue of no room thermostat, are you sure you don't have individual thermostatic valves on each radiator?   It's not uncommon nowadays to use these instead of a single room 'stat so that each room can be adjusted individually.

If there are neither radiator 'stats nor a common room 'stat, then it's not automatically "wrong," just rather cheapskate given that a typical 'stat and cable would have added about £20 to the total price. 

The boiler repair man was here for about 3 hours yesterday.  And the prize for correct diagnosis goes to...pkessler!  It's not a Potteron, but it was the pcb.  Now I'm stuck waiting around the house again today between noon and 6 so he can replace it.  Interestingly, it mysteriously turned on, for the first time ever, in the middle of the night last night.  I woke up in a 24 degree bedroom.   

Hi PR

thats no worries - it's hard to pinpoint stuff over a web forum, but with the amount of dodgy installs around and the points I raised - a very common and worthwhile response!

I wasn't in anyway belittling your post or anything...

Carrie - cool that you got the issue resolved!

Today i'm on the other side of the fence - my tenant today was moaning that the storage heater works sometimes and not at other times - so I should replace it! I'm like hang on a sec, lets work out to see if it's adjsuted and set correctly before you make me go out and spend £250 !

Cheers! DtM! West London & Slough UK!

The boiler repair man was here for about 3 hours yesterday.  And the prize for correct diagnosis goes to...pkessler!  It's not a Potteron, but it was the pcb.  Now I'm stuck waiting around the house again today between noon and 6 so he can replace it.  Interestingly, it mysteriously turned on, for the first time ever, in the middle of the night last night.  I woke up in a 24 degree bedroom.   

Aha! We were plagued with a Potterton with problems for months! I am glad to hear you are warm again.

A bit off topic but we pay £13 a month for British Gas boiler cover. As soon as we moved to this house they came out and serviced our boiler and checked everything over. It's well worth the few £ a month!