Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Craigyk76 Sun Dec 14, 2014 2:01 pm

Hi I have a boilermate 2000 and an ideal slimline classic fe9 FF boiler, the store heats up to temperature and the boiler switches off and the store temperature and hot water work fine, However when I switch on the central heating the store temperature starts to drop and the boiler starts up but doesn't keep it above 60 so the heating switches off. Once the store reaches 60 again the heating comes on for a bout 40 seconds until the temperature drops below 60 again.When the pump starts up the flow and return pipes are cold to the touch so I think it is the cold water going into the store and dropping the temperature below the required 60 deg.

If I don't switch the ch on then the boiler heats the store to what ever temperature it asks for and shuts off.

This was working fine with no problems you could set the thermostat to anything and the heating would stay on until that was met.

I have found other threads here about similar issues but haven't been able to find one with a definitive answer.

Any ideas ? Please

mike Sun Dec 14, 2014 3:00 pm

Sounds like you could have;
Unit low on water; Blocked cold feed.
Unit blocked with sludge.
Pipe work from boiler to unit & back are blocked.
Boiler blocked.
Boiler pump could be the same or end of life.
When the boiler is heating the unit how long does it take for each degree of heat as in temperature C ?
Mike

Craigyk76 Mon Dec 15, 2014 1:36 pm

Hi Mike I've just had a new pump fitted as the old one was failing to start, had the same issue before pump was replaced.if the temp drops from 74 to around 57 it takes a couple of minutes to raise a deg but by the time it gets to 59 it takes around 40 seconds, its strange as the heating works fine when the store is over 60 deg if anything the radiators get a bit to hot house is nice and warm when i got in from work and store was sitting at 64 with the heating on. just not constant heating which might be worse on a really cold day.

Thanks

wardelld Sat Feb 14, 2015 1:14 am

I have the same problem. Store temp happily sitting at 75C. When the heating switches on the store temp drops to 59C and the heating switches off.
I replaced PHE and DHW sensors because they both showed an Error. However the problem persists.
Store is full. Header tank fine. Pump fine.

If I turn on a tap, the demand for the hot water triggers the boiler, raises the store temp and heating comes on... ...for a few minutes until the store drops below 60C.

Any ideas?

mike Sat Feb 14, 2015 2:12 am

PHE sensor & DHW sensor nothing to do with the problem.
Although needed replacing.
Heating will NOT work on a BM 2000 if the unit drops below 60c
Is the store reaching 75c ?
If it is then I would be surprised you are having the problem.
If it does reach 75c and the heating takes the heat away.
Then your boiler is not keeping up.
It may be due to age.
Or the boiler pipes are restricted and the boiler too!
There could be partial blockage inside the BM also.
Heating and DHW works fine.
But the boiler /unit side sounds like the trouble.
Mike

wardelld Sat Feb 14, 2015 2:30 am

Thanks Mike for the quick reply. Probably not a blockage since when I trigger the boiler to fire, either through hot water demand, or resetting the Boilermate2000 it quickly heats the store and the central heating system.
If I keep repeating this (for example if I open a hot tap every 15 minutes) it keep triggering the Boilermate2000 and the boiler keeps up. It is almost as though the boiler isn't responding to store temp demand for heating only.

I will get the boiler serviced but it may be a control problem? The boiler and boiler pump LEDs are both on and the store temp 59C. Annoying!

mike Sat Feb 14, 2015 2:58 am

Can you read the display?
Can you go through the fault codes?
If you can then ACB would be ok.
Right inside the BM there are 2 cylinders.
Left hand one for the heating.
Right hand one for the DHW
There are many various pipes linking the 2 parts up.
The boiler flow & return goes into the left hand one.
Your DHW is ok as when that has heated it will work quite well.
But the left hand one has water which is stored at 75c.
Put the heating on and that the flies round the rads taking that heat away.
Your boiler then has to keep up.
Refer to my last post.
You could try;
Putting heating pump on number 2.
Balancing the heating system.
Or as an experiment turn a few rads off and see whether the boiler keeps up then.
Logic normally wins!
Mike

wardelld Sat Feb 14, 2015 3:02 am

Thanks again. Yes display and PCB ok.

Good logic. I will try those steps.

Dave

wardelld Sat Feb 14, 2015 4:21 am

With CH pump set to 1 the temp drops initially slowly, hits 73C and the boiler triggers as expected. Within 2 minutes the temp is down to 59C and heating off. The boiler barely has a chance to get going!

I will look at the boiler. Thanks.

Craigyk76 Sat Feb 14, 2015 5:05 am

I didn't get a chance to try anything that was sugested I have changed connected the heating pump to the thermostat as a temporary fix so that I can get heating when needed store temp drops below 50 at times when the heating and got water is used but then rises back up to temp and the boiler switches off.

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Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.

Re: Boilermate 2000 hot water and store temperature fine until you switch the central heating on and the store temperature drops below 60 stopping central heating but Hot water still works.