Raytherm Boiler and Controls

Old 09-01-18, 01:29 AM
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Raytherm Boiler and Controls

I have an ancient Raytherm 134T Hot Water Boiler for radiant floor heat to a newly renovated office for my wife. The area used to be a garage and is about 400 square feet across three rooms.

It uses a basic round Honeywell Thermostat, a Grundfos UPS 15-42F circulation pump, and a single zone valve.

The pump runs whenever I switch on power on to the system which also controls power to the 24 volt transformer and the gas valve.

It currently is functioning as a basic system with no other controls but I am wondering if I should/could look at getting something to make it a little more efficient.

Iím thinking that perhaps the pump does not need to run all the time or maybe it does?

Also Iím wondering about the proper way to set the controls in the boiler for best operation. The Modulating Valve and the Heat control in the boiler.
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Old 09-01-18, 01:40 PM
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I'd say you have some wiring issues. If you have a single zone then you don't need a zone valve in the system. Since you do have a zone valve...... when it's closed.... the pump should not be running. You will need to set the boiler temperature low for the radiant floor heating.
Old 09-01-18, 06:33 PM
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PJ, where do you see a zone valve?
Old 09-01-18, 07:08 PM
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You can't see it in the picture, I just said there was one in my description.

The system was used to heat water for a hot tub and the new garage but that was shut off long before I bought the house, I'm assuming it leaked. I have since removed the hot tub and am only needing to heat the office area.

The wiring consists of a regular wall type switch that powers the pump and the transformer when it is switched on. If it is switched off, the pump does not run, nor does the boiler fire up.

The thermostat controls the one remaining zone valve.

The extra wiring you may see in the picture is what I have yet to remove for the other zone valves that have been removed.

I'm trying to figure out how I should control the circulating pump, the zone valve (if needed) and the boiler Modulating Valve and the Heat control.


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