mixing cast iron radiators with heated slab: how to?

[Thom Griffin]

Hello all, I haven't been here much since I put in my system about 6 years ago. I have a Tarm heating cast iron radiators. I want to finally (after 30years here...) finish a small (9 X 13) attached greenhouse and possibly heat it with a radiant slab.

My existing system is a single zone.

How would I pipe and control the water temp for a small radiant slab? I don't think I can put 160 degree water into it, can I?

 

[leon]

Its never good to use hot water that hot in floor heating.
It would be simpler for you to use a hot water garage
heater hung from the ceiling.

 

[maple1]

All you would need is a mixing valve & another circ.

 

[Karl_northwind]

as you'll want it on a separate thermostat, you will need the mixing valve and circulator and a relay for the circulator. just keep in mind that depending on your application (such as the greenhouse type, outside temperature and required temperature) you may not be able to get enough heat thru a small slab quickly enough to keep the green house up to temperature in cold weather. if you find that happen, you may put a large cast iron radiator in line with the hot line to the mixing valve. the radiator will heat up quickly and deliver enough heat sometimes, with the in-floor being a bonus.