Thermguard in boiler room?

[bridgerman]

Try this one...dual pole, $11.18

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=PB488-ND

 

[Glosta]

Kevin - I just ordered the 4 pole double throw relay at Grainger for $48.00 I'm using the Thermguard to control 4 zones.

Here's the link: http://www.grainger.com/Grainger/OMRON-General-Purpose-Relay-1YCH5

John - When using the 24volt Transformer with the 4 pole relay to control all four heating zones, I assume I'll probably lose the "memory" feature of the Thermguard? In other words, in a conventional set-up, the Thermguard will "reset" the programed interval any time the Thermostat calls for heat. When using the transformer and relay set-up to control all 4 zones at the same time, I assume the Thermguard doesn't reset the interval because it's not tied into the thermostat loop. Does that make sense?
"

 

[FordMastertech]

[quote Thanks John for the schematic and thanks Ford for the pics of your setup. How is the cold start achieved? I would rather burn no oil and just circulate the pumps every two hours.

FordMastertech will need to chime in there. I believe he used a "normally closed" contact on the relay to allow the signal to fire the boiler. When ThermGuard kicks in, the "normally closed" contact opens up and disrupts the signal to the igniter. That is what I would do. I am showing a schematic to do this. Don't forget, this doesn't warm the water so you are just counting on the moving water to not freeze. In this case, I would recommend cycling more often.[/quote]
What John is talking about is exactly what I did, used the normally closed side of the relay to control the boiler and the switch when on is a closed circuit to the boiler allowing it it fire normally when using the ThermGuard. As he also stated this setup will not supply hot water to the zones, it will just circulate the water and in my application this is all I need for the temps I see. If it gets real cold I can flip the switch to on and fire the boiler normally and supply hot water to the zones using the ThermGuard. I also recommend to cycle the ThermGuard more often in my setup with the switch in the off position.

 

[FordMastertech]

Sorry I wasn't around yesterday, snow removal and fixing broken plow trucks kept me busy all day.
This is where I got my relay, $7.84, from and I also got the terminal mounting block seeing it was cheap, $1.99. All my local suppliers wanted big bucks for the 4PDT relays and had none in stock. You can get the 2PDT relays from Radio Shack for $8.99.
Midwest Equipment does have a $10.00 low order fee for orders under $25.00 and I didn't see anything on the web site stating that so I ordered some other gizmo's I could or may need later to get it to over the $25.00 but even paying the low order fee was still cheper than the other places I got prices from. They shipped pretty fast, ordered Monday and had it Friday. The rest of the items, DPDT switch, box, resistors, LEDs and diodes were bought from Radio Shack locally. The thermostat and wire I had laying around but can be bought for pretty cheap at Lowe's or HD.
I really would like to find a inexpensive thermostat that monitors outside temps that I can set to come on a real low temps, most only go down to 45 °F
http://www.midwestequipment.com/idec-ru4s-pole-double-throw-relay-with-light-lever-p-417.html

 

[bridgerman]

John - When using the 24volt Transformer with the 4 pole relay to control all four heating zones, I assume I'll probably lose the "memory" feature of the Thermguard? In other words, in a conventional set-up, the Thermguard will "reset" the programed interval any time the Thermostat calls for heat. When using the transformer and relay set-up to control all 4 zones at the same time, I assume the Thermguard doesn't reset the interval because it's not tied into the thermostat loop. Does that make sense?
"

Yes, that is correct. One of the downsides of using the external 24VAC transformer and a relay. You could potentially cycle the zone more frequently than just using a ThermGuard on each zone.

John

 

[jumpink]

Thanks for taking the time to share.