One for the plumbers: Radiator question

[stevie_b]

Background: I have a gravity-fed GCH system, with a hot water cylinder in the airing cupboard. Basically, a standard old-school setup.

 

I'm thinking of changing the radiator in my bathroom from the existing conventional rad to a towel rad. I've heard that there's often a rad in the system that's also connected to the hot water tank, which is used to dump heat from the hot water system if it gets too hot. I've also heard that this rad is often the bathroom rad.

 

I've calculated the towel rad size that my bathroom would need (based on room dimensions). It's possible the towel rad I've ordered has a slightly lower BTU than the existing rad (only by 10%-20%). Is this likely to cause an issue if the bathroom rad is the "heat-sink" one described above?

 

I guess it won't be a problem, but I just want to confirm that the there's usually some margin for "error" when putting in heat-sink rads. Or put another way, would I be able to put in a tiny heat-sink radiator and still be safe from breaking the boiler?

 

Thanks in advance for any help,

Steve

[probrox]

As long as there are no thermostatic valves on the rad then there shouldn't be any problem

[stevie_b]

Thanks probox, that's exactly what I want to hear.

 

Edit: does the "heat-sink radiator" have a proper name that's recognised in the plumbing industry?

[Ark]

Surely if it's the heat sink rad, a thermostatic valve is exactly what you don't want, since it could cut off the rad when it's most needed, ie, when there is excess heat to dump.

[stevie_b]

Surely if it's the heat sink rad, a thermostatic valve is exactly what you don't want, since it could cut off the rad when it's most needed, ie, when there is excess heat to dump.

 

Indeed. That's what probox said. My main concern was whether I can reduce the output of the rad by a bit (i.e. change it to a smaller rad) and still have an effective heat-sink rad.

[Ark]

In fairness, I've never seen a thermostatic valve for a towel rail. If your system gets into a state where it needs to dump so much excess heat that _any_ open rad can't sort it out, then you've got a bigger problem. The main thermostats on the wall and on the hot water tank should prevent this situation.

[stevie_b]

I agree Ark. I'm at the edge of my knowledge here, and what I wrote in the 1st post is second-hand info. Can anyone confirm whether such a heat-sink rad exists?