Kickspace Heater & Monoflow Tee

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  #1  
Old 03-20-05, 10:14 PM
neophyter
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Question Kickspace Heater & Monoflow Tee

I have a question about monoflow tees (a.k.a. venturi tees or diversion tees).

I have a one pipe series loop that supplies about 19' of baseboard. The total length of this run from the boiler loop and back is about 180' (3/4" PEX). Prior to the baseboard, the loop supplies a QuietOne 2006 kickspace heater. The kickspace is above the main. Feeding the kickspace risers, there is a standard tee on the supply side and a monoflow tee on the return side. The ring on the monoflow is between the risers.

http://www.smithsenvironmental.com/html/quietone.html

My question is, is one monoflow tee on the return enough or should there be one on the supply as well?

I know it is typically recommended that monoflow tees be used on both the return and supply if the terminal unit is high resistance. What qualifies as high resistance? Would a kickspace heater in this circuit be considered high resistance?
 
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Old 03-21-05, 03:08 PM
J
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kickspace heater & monoflow tee

I have used Beacon Morris kickspace heaters and I have had to use the monoflow tees on the supply side and return side to get hot water to go through the heater. I also put bleeders on the supply and on the return side of the heater. I know that I only need one bleeder, I do that to make sure I get all the air out of that heater. I am not familar with your quiet-one heater, but I would guess that it would be a safe bet that you would need a monoflow tee on both sides of that heater.
 
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Old 03-21-05, 03:41 PM
neophyter
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Which brand of monoflow tee do you use and what size pipe diameter?

I ask this because the Bell & Gossett 3/4" monoflo tee is only rated to be used on the return side and not both the return & supply sides. I'm not sure why this is but their larger sizes are rated for both sides.

The data on the B&G monoflo tee:
http://fhaspapp.ittind.com/literature/files/602.pdf

The QuietOne unit actually has a built in bleeder on the return, which is accesible through the front panel.
 
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Old 03-21-05, 03:46 PM
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Monoflow & kickspace

Mono-flo's & kickspace heaters are generally not a good mix. Kickspace heaters require a fairly substantial flow to prevent the fan from short cycling.
If I were installing the kickspace heater, I would either put it on a zone of it's own or run it in series with the baseboard, preferably a zone of it's own.
 
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Old 03-21-05, 04:09 PM
neophyter
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Doesn't a 1/2" piping kickspace pose too much of a pressure drop (2.6ft @ 5GPM) to be put in series with the 3/4" baseboard? Wouldn't it bottleneck the flow of the entire circuit?

The kickspace heater instruction manuals that I have read usually recommend a monoflo fitting for one pipe series loops. Obviously, a separate feed would be better.

If I would have known more about this stuff at the time, I certainly would have had my installer run it on a different circuit down to the boiler loop. However, it is already installed and the walls are already sheetrocked/painted so it is too late for that.

It definitely throws out some heat but it still seems to lag a little given the output of this unit and heat loss calcs of the room. It is certainly getting flow through it, I just don't know if it's enough flow.

The floors have not been installed yet, so I can still change the monoflow portion of this circuit, if I need to, through the subfloor.

Thanks for all of the input.
 
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Old 03-21-05, 04:21 PM
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Kickspace heater

Does your heater have a fan on it? If it does, is it controled by time or water temperature? If controled by temperature, does the fan stay on? If it does, you are getting sufficient flow thru the heater. The kickspace heaters with which I am most familiar, have a temperature sensor on the discharge end of the heater which controls the fan. If there is not enough flow or the water temperature is too low, the fan will either short cycle or not come on at all.
 
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Old 03-21-05, 04:34 PM
neophyter
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It has a fan and an aquastat set for 130 degrees, which can't be changed.
 
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Old 03-21-05, 04:40 PM
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Fixed aquastat

Does the fan stay on or cycle on then go off & come back on during the same call for heat?
 
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Old 03-21-05, 05:03 PM
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One tee should be sufficient and the return is the best place for it. Do you have the recommended (20" I think) distance between the tees? You should use full port ball valves if you have isolation on that circuit. I would not suggest series flow through the heater. It will restrict flow through the whole loop. Are you sure there isn't any air trapped in the heater? I have never had a problem with that type of heater and only one monoflo tee. Usually if the heaters output is more than the required amount, we have to reduce the flow with the ball valve.

Ken
 
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Old 03-22-05, 05:12 PM
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Two tees is best I think and I usually pipe them with soft copper so that there aren't any sharp angles. Nice gradual sweeps.
 
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Old 03-22-05, 05:42 PM
neophyter
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Does the fan stay on or cycle on then go off & come back on during the same call for heat?
If I remember properly, I think that it sometimes cycles on and off during the same call for heat.


Do you have the recommended (20" I think) distance between the tees?
It is at least 12" and may even be as much as 20". I have read that 12" is usually the recommended minimum for monoflo tees.


Are you sure there isn't any air trapped in the heater?
I just purged the entire circuit several weeks ago and I just opened the bleeder again the other day. It seemed like only water was coming out.


You should use full port ball valves if you have isolation on that circuit.
What do you mean by isolation? There are no ball valves near the kickspace heater. Where exactly should the ball valves be? Are you saying that I should have ball valves between the monoflo tees and the kickspace heater?


Two tees is best I think and I usually pipe them with soft copper so that there aren't any sharp angles. Nice gradual sweeps.
It is piped with standard copper pipe and there are six 90s leading up to the supply piping. It is a little messy because they had to get around the piping for the sink.
 
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Old 03-23-05, 03:01 PM
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6 90s is alot of elbows
 
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