New Oil Boiler is Short Cycling.

[HandmadeMatt]

Ok I understand. That makes sense. Thank you.

So, I have a final £200 to pay before I get the certificates for the whole system from the firm.

The bathroom and kitchen install that I will be doing myself won't be for some weeks so currently there is no way to use the hot water so it's just turned off at the programmer ever since it was first tested.
Also, as it's unoccupied the heating is just on for the coldest part of the night with the room stat at ten degrees.

This means once I start using it all properly in weeks to come if I do need anything adjusted I will likely attract charges from the plumber surely?
If everything can be set up correctly first time around then it's all included in the price obviously. Unless I should expect "free/ included" after-service for any adjustments?

I don't want to hold back the £200 and the certification for weeks, it doesn't feel reasonable but maybe that's what I need to do?

Cheers.

 

[oilhead]

If you are happy with the rest of the work and you need the certs. why not ask your installer how much it will cost to reset the boiler should it need to be? you may be surprised how reasonable contractors can be.

 

[Agile]

With the possibility of freezing weather my advice would be to leave the heating 24/7 but with the room stat at about 3 C so that it only brings the heating on when its really cold.

Just putting it on for a couple of hours does not protect against when its really freezing a few hours later.

Tony

 

[HandmadeMatt]

If you are happy with the rest of the work and you need the certs. why not ask your installer how much it will cost to reset the boiler should it need to be? you may be surprised how reasonable contractors can be.

I think you're right. I'll just ask him.

With the possibility of freezing weather my advice would be to leave the heating 24/7 but with the room stat at about 3 C so that it only brings the heating on when its really cold.

Just putting it on for a couple of hours does not protect against when its really freezing a few hours later.

We're only experiencing slight frosts so I am not concerned.
I'm in the house every morning from 9am working through until the evening. When I first go in I can feel the residual warmth from the heating.
I light the wood burning stove if it gets really cold whilst I'm working.
My room stat starts at 10 degrees. Maybe I'll get a new one that has a bigger range for future vacancy frost protection.
All the pipes are lagged and well insulated too.

Something I was wondering though, when the boiler fires up under it's own frost protection system the primary and return will just whizz around the bypass right? (The hot water and central heating valves would be closed.)
So if I left the central heating valve manually held open then would it also send heat around all the radiators?

If that's the case does anyone know how that frost protection works? Does it run and wait for the primary return to get up to temperature before it shuts off or is it a timer or what?
I've not observed it doing yet, it's not been cold enough whilst I'm around.

Thanks again for all your advice guys.

 

[Agile]

Yes, that would be a good idea to manually set the heating zone valve open. But be aware that it loses its manual setting the first time that it opens on power!

Boilers mostly use one of their existing temperature sensors to indicate that the temperature is dangerously low.

In most cases there is a two stage process, the first at 5 C just runs the pump. The next is to fire up the boiler if below 3 C.

Tony

 

[oilhead]

Your boilers frost protection relies on a thermostat in the case, and it keeps the boiler warm, and it is a single stage thermostat (Tony, you really should stick to gas!!).
Do you have a separate frost thermostat in the house? If not, then you could replace your room thermostat with a programmable unit, and leaving the heating on constant, control it with that thermostat. I would be wary of lowering your room stat to 3oC as it leaves no margin for any vulnerable spots near to the flow and return pipework to an external boiler.

 

[HandmadeMatt]

Do you have a separate frost thermostat in the house? If not, then you could replace your room thermostat with a programmable unit, and leaving the heating on constant, control it with that thermostat.

I've been thinking about a programable one. I'll look into it.

I would be wary of lowering your room stat to 3oC as it leaves no margin for any vulnerable spots near to the flow and return pipework to an external boiler.

Fair point.

Yesterday I did an experiment. I let the whole system warm up to full operating temperature and then went around and shut all the TRV's down to frost protection setting. I left one radiator on max.
In this case the boiler still had a much longer off time but only a one minute run time before the internal return flow thermostat reaches temperature.

Is it reasonable to have the central heating on 24/7 and all the TRV's turned down to the frost setting? (Or just above the frost setting?)

My only concern is that the boiler could easily fire up over a hundred times a day, surely that can't be good for it's longevity?

 

[oilhead]

As I referred to in an earlier post, just think how often a combi fires up for each time a tap is turned on. I don't think you have a problem. My own gas boiler does just what yours does, and has done for 15 years. When you are in residence, You will have a thermostat controlling at a comfort temperature, so it is reasonable to assume that there will be significant off periods when your temperature is reached.
With regard to your query about constant heating, set your trv's for a low setting, but also set your room stat for a safe temperature. Whilst the ambient temperature is above your setting, your boiler will not run.

 

[HandmadeMatt]

You've really helped me understand the system mate, thank you.
I feel confident now.
(It's the first time I've ever had central heating in my life and it's a system that I was involved with designing the whole way along. It feels really good.)

 

[Agile]

(It's the first time I've ever had central heating in my life and it's a system that I was involved with designing the whole way along. It feels really good.)

That could be worrying somebody involved in designing something that they have absolutely no knowledge of.

 

[HandmadeMatt]

That could be worrying somebody involved in designing something that they have absolutely no knowledge of.

Nothing to worry about mate, I've had great support.

 

[oilhead]

Involvement is no problem. If an individual can communicate his requirements to a professional who is also able to translate them into reality, and is able also to produce something other than what he has always done, then it should be applauded.
If it happened more often, then we would not have the many catalogues of disaster we try to resolve on forums like this