Non-valved radiator

pablakeman

I am in a new build house and both our thermostat and non-valved radiator are in the hallway.

It seems to me as if that non-valves radiator heats up really quickly such that we need to have the thermostat at too-high a temperature. 

Is it likely that this radiator has the purpose of being very slow to heat up but is in fact misconfigured and heats up too fast? (Or is it likely that this doesn’t have a valve to allow a constant flow?)

Any help appreciated, or just to understand a bit more. We are looking at getting a different thermostat soon as we want one we can move to a colder room to help the whole house - but it might just be that we aren’t understanding something.

MWT

When you say 'non-valved' I assume since this is a new build you mean it doesn't have a Thermostatic Radiator Valve on it?

It will have a valve at each end, one usually covered to prevent casual adjustment (Lock-shield) and the other manually adjustable.

This is a normal arrangement and ensures the water always has somewhere to flow if the TRVs have all shut down.

Then each of your other rooms probably has a thermostatic valve fitted so you can adjust the temperature in each room.

It is possible that you may need to reduce the flow by adjusting the lock-shield valve a little , but only if you find the area with the thermostat and the radiator without the TRV is heating too quickly.

It would probably be worth getting a plumber in to check you have the flow through all the radiators properly balanced.

It is a relatively quick job and should not cost much, or google it and follow the instructions yourself if you want...

Moving the thermostat isn't really the way to go, the TRV's on the other radiators should take care of that if the flow is properly balanced.

Talldave

As @MWT says, reduce the flow to the hall radiator and that will allow the system to heat the whole house a bit more before the hall thermostat is satisfied. You might be able to lower the thermostat temperature a little to something more realistic so the hall doesn't end up like a sauna.

If you move the thermostat elsewhere you might end up with a lock out, where the room TRV is satisfied and shuts the radiator off but the thermostat keeps the boiler running in a vain attempt to get the room warmer. End result is the hall being a sauna and increased gas consumption!

Farway

MWT said:

When you say 'non-valved' I assume since this is a new build you mean it doesn't have a Thermostatic Radiator Valve on it?

It will have a valve at each end, one usually covered to prevent casual adjustment (Lock-shield) and the other manually adjustable.

This is a normal arrangement and ensures the water always has somewhere to flow if the TRVs have all shut down.

Then each of your other rooms probably has a thermostatic valve fitted so you can adjust the temperature in each room.

It is possible that you may need to reduce the flow by adjusting the lock-shield valve a little , but only if you find the area with the thermostat and the radiator without the TRV is heating too quickly.

It would probably be worth getting a plumber in to check you have the flow through all the radiators properly balanced.

It is a relatively quick job and should not cost much, or google it and follow the instructions yourself if you want...

Moving the thermostat isn't really the way to go, the TRV's on the other radiators should take care of that if the flow is properly balanced.

This in bold, being new build I very much doubt the radiators have been balanced, just a fit & forget installation

I'd try & do the balancing yourself, plenty on You Tube & search engines, it's not a difficult or technical job

It can be a lengthy process involving waiting and if not DIY then you will be paying an hourly rate to someone while they sit around waiting for temperatures to be achieved

[Deleted User]

pablakeman said:

I am in a new build house and both our thermostat and non-valved radiator are in the hallway.

It seems to me as if that non-valves radiator heats up really quickly such that we need to have the thermostat at too-high a temperature. 

Is it likely that this radiator has the purpose of being very slow to heat up but is in fact misconfigured and heats up too fast? (Or is it likely that this doesn’t have a valve to allow a constant flow?)

Any help appreciated, or just to understand a bit more. We are looking at getting a different thermostat soon as we want one we can move to a colder room to help the whole house - but it might just be that we aren’t understanding something.

In theory, an open radiator should be not be necessary on a new build heating circuit. It goes back to the days of gated bypass valves. My ‘new build’ of 2 years ago has TRVs on all the radiators; heating rails etc. The minimum boiler flow rate is maintained using an Automatic Bypass Valve which connects the flow side of the system to the return side when radiator valves are partially or fully closed.

MWT

Dolor said:

In theory, an open radiator should be not be necessary on a new build heating circuit. It goes back to the days of gated bypass valves. My ‘new build’ of 2 years ago has TRVs on all the radiators; heating rails etc. The minimum boiler flow rate is maintained using an Automatic Bypass Valve which connects the flow side of the system to the return side when radiator valves are partially or fully closed.

The risk of that though is as Talldave mentions above, if you set the TRV on the radiator closest to the thermostat too low, you may never achieve the required temperature and the system keeps pumping.

The automatic bypass will help maintain flow, but you also need something to shut down the boiler if all the TRV's are closed...

Cardew

New build houses should now have two zones. That said for houses less than 150m2 it is not mandatory. I assume the 150m2 is for all floors i.e. 75m2 per floor in a conventional 2 storey house??

'The automatic bypass will help maintain flow, but you also need something to shut down the boiler if all the TRV's are closed...'

The boiler will shut down when the circulated water has reached the temperature set on the boiler, which in these days of condensing boilers is much lower than yesteryear; not ideal I appreciate as it will cause cycling.

There is an interesting discusion on TRVs zones etc here.

https://community.screwfix.com/threads/multi-zone-heating-in-new-build.222732/

JC_Derby

The radiator in the hallway with the thermostat SHOULDNT have a TRV. I think it’s called a check radiator - (im probably wrong and it’s called something else). But as I understand it the trvs will help control the temperatures in other rooms but the check radiator shouldn’t be messed with because the hall thermostat controls the heating for the whole house...ie if you turned that radiator off, the heating would just keep on running as the hall stat would never get to temperature.
if you have c9ld rooms in the rest of the house it very much sounds like the system is not balanced.... do you have cold radiators, or just colder rooms? You then need to understand why those rooms are colder...is the radiator in that room heating properly.

[Deleted User]

JC_Derby said:

The radiator in the hallway with the thermostat SHOULDNT have a TRV. I think it’s called a check radiator - (im probably wrong and it’s called something else). But as I understand it the trvs will help control the temperatures in other rooms but the check radiator shouldn’t be messed with because the hall thermostat controls the heating for the whole house...ie if you turned that radiator off, the heating would just keep on running as the hall stat would never get to temperature.
if you have c9ld rooms in the rest of the house it very much sounds like the system is not balanced.... do you have cold radiators, or just colder rooms? You then need to understand why those rooms are colder...is the radiator in that room heating properly.

Times have moved on. If TRVs are fitted to all radiators then no thermostats are actually required. The downside of not having a thermostat is that some method has to be found to communicate with the boiler when heat is no longer required. ETRVs (such a Honeywell Evohome HR91/92)  can instruct the boiler to turn on and off in line with heating demands for a particular zone. These instructions are passed to the boiler via a programmer/timer rather than an ON/OFF or standard TPI thermostat.

All that said, most modern boilers have a minimum flow rate and a pump overrun time. When the boiler stops firing when there is no heat demand, the pump needs to be kept running. My boiler pump overrun is set to 6 minutes. This allows heat within the heat exchanger to dissipate. It follows that there needs to some form of interconnection between the flow and return lines in a CH system. For years, this was achieved by either leaving a radiator open, or a gated bypass (a copper pipe link with a standard On/Off tap which was left slightly open). Today, the preferred solution is an Automatic Bypass Valve. My new build home has 2 heating zones (Tado thermostats); TRVs on all radiators and a calibrated Automatic Bypass Valve.

People talk a lot about balanced systems and there are those that are for it, and they are those who think that it is unimportant. In my view it is more important when a CH system first comes on to ensure that heat is spread evenly across the whole system. I suspect that most of us have one radiator that is last in the queue to heat up. However, once a system is fully up to temperature and individual TRVs are opening and closing, then balancing is really not that important.

Finally, whilst the majority of homes still have the old wired thermostat, we shouldn't forget that most smart thermostats are now portable - that is, they can be put in any room in the house. Clearly, if a smart thermostat is placed in a room with a standard TRV, then the TRV setting must be higher than the temperature set on the smart thermostat. To do otherwise would negate the reason for putting the smart thermostat in the room.


 

Talldave

The problem with most heating systems is the user.  We were brought up with one thermostat systems.  Even worse, a lot of people thought that domestic thermostats worked like older car heaters worked - ie: cranking it up gives out more heat! I've seen many people arrive hone to a cold house and crank the thermostat up to 30 - thinking that that will make it warm up faster,  which it doesn't,  it merely sets the level of sauna like atmosphere you’ll be subjected to later.

Multi-zoned systems with individual room thermostats are brilliantly flexible, but most people can't get their head around them.