Number of TRVs in one room?

[Mikomotor]

Hi,

I'm aware from previous posts that in the room with my system thermostat (the hall) I need to ensure that I leave the hall radiator without a TRV.

In a couple of other rooms I have two rads. In this situation, is it recommended that I only fit one of the rads with a TRV?

Thanks,
Mike.

 

[simon_d]

Hi,

I'm aware from previous posts that in the room with my system thermostat (the hall) I need to ensure that I leave the hall radiator without a TRV.

In a couple of other rooms I have two rads. In this situation, is it recommended that I only fit one of the rads with a TRV?

Thanks,
Mike.

whats the point in only havin 1 TRV? once it gets to temp the other rad will keep heating....

 

[corgiman]

the only rad that does not have to have a trv (part L ) is the located in t he same room as the boiler interlock (room stat)

 

[AndersonC]

What's a boiler interlock? I will be putting a rad in the same room as the boiler, so would this therefore not require a TRV but a room stat?

One problem though is that it's a spare bedroom so I'll be less bothered about the temperature in there than in other rooms, I might turn the rad down to reduce the enrrgy use as the room won't get much use.

Does this have the potential to cause a problem if I were to put a room stat in there?

 

[bster]

In a single zone heating system only one room stat should be used (usually hallway), trv's to all rads except the room with the room stat on.

(dont put room stat where there is a secondary heat source i.e. fire).

Dont put room stat in bedroom, just a TRV.

Boiler interlock is created through the use of a set of controls (cylinder stat\room stat) that prevent the boiler firing unless there is a demand, this prevents the room being constantly heated when it doesn't need to be and it also prevents boiler short cycling were the boiler is switching on-off-on-off-on-off through the boilers hi-limit stat. - all saves energy\money.

 

[corgiman]

as bster says a boiler interlock is simply a electric stat that turns the boiler off, which trv's dont

dont know why i posted this, but it does a treat for the post numbers

 

[garethgas]

Its all good stuff until someone knocks then the front door is opened.

 

[Paul Barker]

Similarly at the other extreme some halls which have hardly any external walls and are very small spaces (i.e. modern houses) heat up in a 5 minutes and stay warm for the rest of the day whereas the lounge with two outside walls and a long window get's chilly, so you turn on the 50% efficient gas fire and leave the 91% efficient boiler at rest.

Therefore you don't blindly put your rstat zone in the hall.

Most of the time the lounge is more suitable, as long as you are trained to use the efficient heating not the inefficient fire.

 

[bster]

best thing to use is the Honeywell 'CM Zone' TRV things that are actually linked to the boiler, providing interlock without a room stat - effectivly creating a zone in each room. - expensive though.

 

[croydoncorgi]

There is NO single 'thing' called an 'interlock'.
It's a DESIGN PRINCIPLE.
It's a feature of the design of the system that prevents the boiler from firing when there is no call for heat. That's ALL it means.

An interlock CAN use a room thermostat.

But it can also be built into the boiler - flow switch senses low flow to rads and turns the boiler off for a while.
It can be an external temperature sensor (ie. a weather compensator) which shuts down the heating entirely when the outside temperature rises to a certain point, and adjusts the radiator temperature according to the weather.

 

[bster]

CroydonCorgi

I remember reading about a Baxi 130HE (i think) that controlled the CH by a flow switch (or something), meaning that as resistance rose the burner would mod or shut down, as long as there are TRV's on every rad i presume you dont need a roomy. What other boilers have this feature?

 

[ChrisR]

Several condensing baxi/potts have a flow switch. Sits in the outlet from the combustion chamber. Here's a prety pic of one and why they leak sometimes when the arrowed screws are too long. They also stick open..

 

[croydoncorgi]

Several boilers use flowswitches on the Flow to check for circulation (ie. as a safety feature, instead of a pressure switch). A smaller (?) number use this switch also as an interlock. MI will clearly state which.