Hot Water Radiator Valves and Unions - Do all radiators need a valve?

HandyFS

Do all radiators in a hot water system typically have a radiator valve? Is it common to close a valve partially and keep others fully open based on how much heat a radiator generates in a room? I've never had a boiler/radiator setup so I'm hoping someone can help me understand if its common to adjust/set, and then forget. Is that common practice when getting radiators dialed in?

I've seen some people on the web say that they normally stay fully open, and are only shut off if a radiator needs to be removed/repainted in a system. Someone suggested to install 2 unions, one on each side and don't bother with a valve, but it seems to make sense to have a valve at each radiator for the chance it needs to be removed, etc.

I've seen some of the European systems have a Thermostatic Radiator Valve (TRV) on each radiator which seems like a great idea, but are these as common on Cast Iron Radiators or are those more for the newer aluminum style setups? The cost of TRV's is a lot more than a standard hot water radiator valve. Is it worth thinking about TRV with a cast iron setup, or am I better off with regular valves?

I'm replacing a few radiators in a property I recently purchased. Some radiators were damaged and I'm working on replacing them. I have properly sized radiator replacements and the union spuds removed, so I'm now at the stage of buying new hot water radiator valves and unions.

Do people typically use the manual hot water valve to throttle water flow and dial in temperature, or are they typically just fully open?

mattmia2

They can be used for adjustment. You can put a TRV vale in without a head and add a control head later if you need it. You need a valve on the supply and return if you are going to shut the radiator off to remove it. Also probably want to drain it in the boiler room somehow before you remove it. There are european valves with a lance that can feed from one end. There are european style dual valves. TRVs will only work if the radiators have some sort of individual supply and return.

There are lots of options. If you are heating the whole house and the radiators were sized correctly you should be mostly able to balance things with just the radiator valves. TRVs are a good option in places with varying heat loads like a kitchen or someplace with a lot of solar gain.

HandyFS

mattmia2 said:

They can be used for adjustment. You can put a TRV vale in without a head and add a control head later if you need it. You need a valve on the supply and return if you are going to shut the radiator off to remove it. Also probably want to drain it in the boiler room somehow before you remove it. There are european valves with a lance that can feed from one end. There are european style dual valves. TRVs will only work if the radiators have some sort of individual supply and return.

There are lots of options. If you are heating the whole house and the radiators were sized correctly you should be mostly able to balance things with just the radiator valves. TRVs are a good option in places with varying heat loads like a kitchen or someplace with a lot of solar gain.

Thanks for this, helps me better understand how these systems typically function. Since this property is brand new to me and I have no connection to anyone from the past, I'm uncertain if the radiators are sized correctly or not, but from some general heat loss calculations, it seems that they are proper for the way they were sized when the house was built. I should find out this season once things are finally all up and running, hopefully soon.

I'm going to stick with 1 valve on each radiator inlet to give me the option of flow control. Thanks again.