Boiler problem?

[JonK]

I have an ideal classic boiler located in my garage with a frost stat etc, with honeywell c/p in the kitchen and a honeywell stat on my lounge wall.

The problem is as follows, when we call for c/h to come on it fires up for around half an hour and makes the rads lovely and warm and heats up the whole house. The boiler then shuts down but then comes back on again for a few minutes then shuts down again and so on and so for the next 20 minutes thats it's schedulled to be on for.

The interesting thing is that the room stat doesn't seem to be altering it's temperatures it clicks on and off at around 8 & 12 degress respectively. If I go to the room stat and click it off then on again when the boiler has turned itself off it fires the boiler back up again straight away.

THe house is obviously warmer then 10 degress could it be the roomstat?

 

[Agile]

It sounds very likely but what happens if you set the room stat to maximum like 30° C.

Since a room stat is very cheap then you might as well change it anyway if you are competent to do that.

Tony

 

[JonK]

Thanks for your reply

If I adjust the the stat to say 21 degress +, it never gets hot enough to activate the stat to turn the boiler off, althought the boiler still cycles and the rads are lovely and hot and the room is nice and warm

There is actually a small picture hanging from the stat that my daughter put on there could this be restricting the air flow to the stat, does the probe? get dusty, are they easy to open up and clean out etc?

 

[bigbow]

Sounds as though it hasnt been wired correctly. A room stat should be able to turn on a boiler if the programmer is set to off.

 

[gas_man_gaz]

Sounds as though it hasnt been wired correctly. A room stat should be able to turn on a boiler if the programmer is set to off.

no it shouldn't

 

[bengasman]

Sounds as though it hasnt been wired correctly. A room stat should be able to turn on a boiler if the programmer is set to off.

could you be so kind to explain how that is possible?

 

[bengasman]

Thanks for your reply

If I adjust the the stat to say 21 degress +, it never gets hot enough to activate the stat to turn the boiler off, althought the boiler still cycles and the rads are lovely and hot and the room is nice and warm

There is actually a small picture hanging from the stat that my daughter put on there could this be restricting the air flow to the stat, does the probe? get dusty, are they easy to open up and clean out etc?

i doubt the picture would have a lot of influence on the stat, but hey, take it off for a couple of days and you will know for sure

mechanical roomstats can be quite inaccurate, 5 degrees is not unheard off.
have you checked with an accurate thermometer near the roomstat?

 

[JonK]

Not yet, I will thou over the weekend, am gonna check for air locks too, apparently they can cause cycling on an ideal classic.

 

[bengasman]

The boiler then shuts down but then comes back on again for a few minutes then shuts down again and so on and so for the next 20 minutes thats it's schedulled to be on for.

surely your boiler is on for more than an hour at the time?

if all your rads get warm, airlocks would not be the first thing i would be looking for.

if i remember correctly, classics don't modulate so once the system is warm, they will only be on for short periods of time, that would be normal.

 

[apb]

in all fairness i would first check the frost stat is not set to high this will overide all other external controls

should be set at about 0 to 3 deg depending on how you fell

also try taking the cover off your room stat and check for lint (fluff)
you can use a hoover to clean

 

[bengasman]

also try taking the cover off your room stat and check for lint (fluff)
you can use a hoover to clean

turn power to boiler off before you do this, some stats work on 230!

 

[gas_man_gaz]

in all fairness i would first check the frost stat is not set to high this will overide all other external controls

should be set at about 0 to 3 deg depending on how you fell

also try taking the cover off your room stat and check for lint (fluff)
you can use a hoover to clean

why check the frost stat? the op is saying the roomstat dosnt indicate a change in temp even wen it's been on a few hr's. either the room which the stat is fitted in hasnt changed temp or there's a fault with the stat.
as for the boiler cyling on and off, it will do wen it gets up to temp