Heating issue in empty house

Skint_yet_Again

Can anyone advise please. Empty house insurance stipulates heating on constant at 15’. The thermostat is on the hallway wall just inside the front door. The boiler is 4 years old and recently serviced. I understand it is a sealed system. The thermostat says the overall temperature is 15’

So I’m not sure if there is a problem but 2 of the downstairs radiators have the trv fully open and are cold. One of these is next to the thermostat. The pipes at either end of the radiators are also cold. The 3rd downstairs radiator in the kitchen (nearest the boiler) is cold & doesn’t have a trv. I seem to recall this is the bypass (?) radiator. 

Upstairs the bathroom radiator is boiling hot with two bedroom radiators are warm. All have trv on full. Then up in the loft conversion room the radiator is half hot top to bottom from trv side to centre of the radiator. 

Any basic explanations or advice would be appreciated. I will get the heating engineer back if necessary 

I tried turning the bathroom & bedroom trv’s down to 2 but other radiators still not hot when checked at 10am and 6pm. Thermostat still says 15’

I wondered about turning trv off on the hot radiators & see if downstairs ones get hot if I set thermostat to 20’ ? 

When I first tested the system (before service done) I turned all trv on full (didn’t touch the bypass radiator) put heating to 18’ and all radiators started getting warm apart from the loft room. After turning the trv on and off a few times on the loft rad it started warming up too. 

Not sure if this is normal at 15’ or what the logical order is to test what is going on?  

Emmia

Have you bled the radiators? Are they cold top to bottom?

Skint_yet_Again

I was told you shouldn’t bleed radiators in a sealed system? 

Skint_yet_Again

Sorry the downstairs ones are totally cold all over and none of pipes are warm at either end. The loft conversion room is hot top to bottom but only halfway across. The bathroom and bedroom are hot all over. 

(Sorry edited to make explanation clearer)

gjcody

Skint_yet_Again said:

I was told you shouldn’t bleed radiators in a sealed system? 

You should bleed radiators on a sealed system, though you must re-pressurize the system. Normally, somewhere near the boiler you will find a flexible pipe, this connects fresh water pipe (so to speak) to the heating system pipes. This by rights should be disconnected so you may have to re-connect it for the job. The operation of the values is pretty simple, once the pipe is connect turn the knob on either end and the water will flow. Do not leave it unattended when open and do not just pile water in to the system, to save you having to do it again, that doesn't really work.

Near that or on the boiler there there will be a pressure gauge normally reading 1–5. Find the Manual for the boiler and look what pressure the system should be at, normally it is around 1 and 1.5 bar when cold.

So, with the system cold and all the valve open bleed all the radiators, popping back now and again to check the gauge and if necessary topping the system up.

It can take some time, the water will settle and the air will rise to the top, so give it 15 mins and bleed them all again.

You said the TRVs were open, but there is a valve at the other end called the lockshield, ensure that is open too or the water will not flow. Normally has a white plastic cover; remove that and beneath you will find a 'blade' sticking out which can be turned with an small adjustable spanner or a pair of Grips.

It isn't rocket science, but whatever you do don't over pressurize the system! If you do drain some of the water out using a garden hose on the drain valve.

Good luck; patience is the key.

WIAWSNB

A few points:
1) all systems need bleeding at times, sealed or not. Do you know how to do this? If so, then it's the obvious first step. Turn the boiler off when you do this. If air does come out, then let it all escape, and note how long it hisses for - report back. If the system is sealed - pressurised - then it'll likely need topping up afterwards.
2) if the wall stat is in the room - hallway - with a non-functioning radiator, then it'll never reach 15oC, so the boiler will never be turned off. That needs sorting.
3) the TRVs on every other radiator (other than the wall 'stat radiator) should be turned down to a 15oC 'equivalent', which is '2'. Hopefully that will stop them becoming silly-hot and wasting energy, and it'll also send more flow to the still-cool rads as they shut off, hopefully getting them working too. 
4) then you figure out what's wrong.
Ok, how well do you know this house? Is it 'big'? Could there be more than one wall stat fitted, eg one on each floor?
What boiler is it - photo please. What is the CH output set to?
What wall stat is it - pic please.
Is there a hot water cylinder.

Skint_yet_Again

Thanks for the advice Emmia and gjcody. I think that might be beyond my capabilities. 

When I first turned on the system I checked the pressure first by pressing buttons on the digital readout on the boiler & it was within the stated range according to the instruction book. No pressure gauge. Then when heating turned on, thermostat set to 20’ and all trv opened all radiators were getting hot. It’s only since thermostat set to 15’ that this has occurred. I will try turning it up to 20’ again and see what happens. I could probably manage to bleed radiators but not sure about topping up the system or balancing (which I have looked up online). 

I have my own plumber coming to my house to fit a radiator so I can ask him to look at it if it’s beyond me as empty house is nearby.

silvercar

Skint_yet_Again said:

Thanks for the advice Emmia and gjcody. I think that might be beyond my capabilities. 

When I first turned on the system I checked the pressure first by pressing buttons on the digital readout on the boiler & it was within the stated range according to the instruction book. No pressure gauge. Then when heating turned on, thermostat set to 20’ and all trv opened all radiators were getting hot. It’s only since thermostat set to 15’ that this has occurred. I will try turning it up to 20’ again and see what happens. I could probably manage to bleed radiators but not sure about topping up the system or balancing (which I have looked up online). 

I have my own plumber coming to my house to fit a radiator so I can ask him to look at it if it’s beyond me as empty house is nearby.

The digital readout is giving you the pressure, you don’t need a separate gauge. If it is within the stated range that is fine.

If all the radiators heat up when the thermostat is at 20 then that is also a good sign. 

Try turning the upstairs radiators TRVs down to ‘2’ and then turn the thermostat back up to 20. See if that heats the downstairs radiators.

Skint_yet_Again

Thanks silvercar. I will try that later today and see what happens 

littleboo

The pin on the TRV may be stuck in the off position

Skint_yet_Again

I have turned the heating up from 15 to 20 and all radiators have got evenly hot. Must be something to do with having it set at 15’ 
I think the boiler has a pre-heat function for hot water (Worcester green star 4000) and wonder if it’s this, but can’t find any instructions in the installation and maintenance instructions how to turn it off. Think I need eco mode.