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snow melt (8 Posts)
snow meltI will be using a brazed plated heat exchanger for a snow melting job....question is how to control it.....i want to use a tekmar control #665....or #667 but the #667 just shows a boiler just for the snow melt in the application brochure.....with out a heat exchanger ...can the #667 with injection pumping be used with a heat exhanger...???....boiler heats home too thanks Paul S
HTXWhat I did was use a high flow zone valve to feed boiler water to the flat plate. The Tekmar control opened the zone valve and the zone valve started the boiler.
ONE important thing you need to know though is you will have boiler water without antifreeze on one side of a piece of metal inside the flat plate and potentially sub freezing snow melt water on the other side. If the zone valve fails or the boiler doesn't heat You are going to freeze up the flat plate.
What I did was install a well and aqua stat on the boiler outlet port of the flat plate and set it for 36*. If the boiler water coming out of the flat plate is below the set point it turns the snow melt loop pump off until it warms up. Don't use a strap on aqua stat it won't respond fast enough.
zone valveWhen the zone valve opens does it turn a pump on too??.....to move water through heat exch. And can you give me a example of a high flow zone valve??....bigger size valve?...low CV?.....and if I wanna use injection pumping can I use it with a heat exch? Thanks Paul S
667The 667 will give you more control. You can provide boiler protection and restrict the delta t to the snowmelt. This insures that the house will get it's share.
What Steve is suggesting would work better with a 665. I agree with his point about freezing the exchanger. Oops!
pumpThe 667 will control the snowmelt pump AND open the HEAT zone valve.
The heat zone valve will open and turn on the boiler pump and boiler.
You Will need a control like the Tekmar 667 to control the snowmelt and ensure that you maintain a minimum boiler return temperature.
The size of the pumps, zone valves and heat exchanger depends on the amount of heat needed for your snowmelt system.
And you want a high Cv valve.
A valve with a Cv rating of 8 will flow 8 gallons per minute of water with 1 PSI of pressure drop.
A Cv of 16 will flow 16 gallons at 1 PSI.This post was edited by an admin on December 1, 2013 12:08 AM.
snow meltOk....so basically the 667 control would give me alot more control than the 665....for example if there are other space heating zones off the boiler... i drew out a simple schematic of how i would pipe the snow melt using the 667...but in the 667 manual it shows that it controls the system (primary)pump but at this job the primary pump is controlled when the boiler comes on....also the 667 requires injection pumping in my drawing can i use the injection pump the way i have it? any insight thanks Paul S
Taco XPBI've used the Taco XPB with great success. I think it's a Tekmar injection controller with a 006 injection and 008 system pumps with the HX all in one. Makes for a nice clean install for basically the same price as all the components it replaces. All bronze and SS.
TaylorAlways keep learning: observing what works, and what doesn't. Ask questions
Taco XPBThanks I will look into that , andwil probably use it..but can anyone tell me if my drawing would work with the 667 thanks Paul S