Toekick heater install question

JP123

Hi,

I have two Beacon/Morris K42's and one K84 hydronic toekick heaters. All of which were installed incorrectly by a contractor. The two K42's have been plumbed in series with each other and also plumbed in series with the downstairs heating loop. The K84 is plumbed at the END of the return line with "scoop" tees which the tees are only about 8 inches apart. To top it off, I'm finding that the pex-type pipe used to plumb these is the wrong type as it is only rated for 200 degrees and the pipe is not oxygen barrier rated.

Needless to say, we have air in the system which after purging, eventually returns. The room directly downstream from the two K42's has the thermostat and this room and the room beyond always feels chilly. This is a 2 loop (upstairs and downstairs loops), one zone sytem.

I'd like to get all three toekicks replumbed so that they are on their own separate loop and restore the original downstairs loop. Concerning the toekicks, what would be the best way to plumb them in their own loop? Would they be plumbed in series, parallel, or with scoop tees? I've attached a schematic of the current system design.

Although I will be hiring a professional to do the work, I want to make sure it is done properly, since the last contractor did not complete the work correctly. This is the reason for asking here.

Thank in advance for your help,

John

Al Letellier_21

toe kick heaters

John, according to your sketch, the kitchen heater is piped properly. IF two diverter tees were used!! The spacing should be further apart to even out the flow in the main between the tees. It is the last heater on the loop so it is seeing lower temperatures and therefore its output will be less. It all depends if this system was calculated properly.

The other two heaters can work but would be better if on diverter tees. If you go to a separate loop, install another circulator just for the toe heaters. They have a lot of resistance to flow and show almost never be installed in series unless properly sized along with the piping and circulator.

Do consider using a heating pro. Piping will have to be reconnected differently in you add a circulator and is not a job for someone with limited experience in heat piping. Good luck

JP123

Toekick install

Thanks for the reply Al.



My thought is to have these three installed on their own loop to prevent them from scavenging too much heat from the downstairs loop right before the room with the t-stat which is downstream of the toekicks in the dining room.



I'm not having any luck with Beacon/Morris as to the recommended design for this application since we are in bewteen holidays. I guess I'm trying to find out what would be the recommended design BEFORE I call a contractor so that I can be sure the job is being done properly.



John

icesailor

Toekick Install:

Like someone said, one is correct, the other two are not. If the other two were connected with mono-flows, it would be as correct as possible. If you pipe them direct, the temperature drop through the two units will drop the baseboard performance. Not even getting into the issue of pressure drop. One K-42 heater equals 7' #30 Slant/Fin baseboard at 180' water.

I've been on these calls where the K-42'a were piped in series to a second floor bathroom and the next rooms were cold. And no way to fix it unless you ripped down the ceiling.

JP123

Toekick install

By saying the one is correct - even though it is at the END of the return loop? The other two I sensed were definately installed wrong.



Would the diagram below be a viable design?

JP123

Another idea

I'm also attaching the diagram below. I'm worried this one will allow the 3 TK's to siphon off too much heat before it gets to the room with the thermostat (dining room).



John

Gordan

Maybe

Or maybe not. The problem with piping systems with multiple circulators the way you show there is that the circuits are not hydraulically isolated from each other, so the circulators could affect flow in each other's circuits. Why not just pipe in the third branch in the same way that the other two are piped - in parallel, using the same circulator, and with balance valves? The diverter tees are a good idea since they'll ensure that the downstream toekick heaters don't get water that's too cool. Make sure that your pipes are sized appropriately to even out the pressure drop across that third branch. Also, you should be pumping away from the expansion tank, not toward it.

Gordan

Yes...

You're right to be concerned about the temperature drop.

JP123

One way check valves

How about adding check valves?



I'm all about making the system simple, though I'm worried if one pump will be enough?



As far as the expansion tank, I'm going by what I have seen in system designs. Where should the expansion tank be for this system? Currently, the tank is tee'd off the water fill, just after the auto-make up fill valve. There is also NO air vent on the supply manifold or water inlet at the boiler.



Thanks again,

John 

Gordan

What are you trying to achieve?

If you're not going after a zoned system, you don't need check valves and you only need one, appropriately sized, circulator.



Keep it simple.



Just downstream of the expansion tank is the best place for the circulator.

icesailor

Toekick install:

It doesn't matter how you do it. As long sa you use mono-flows. Use the two speed fan switches to control the heat. They are usually oversized for where you are using them. Set them on low speed. They are quieter on low speed. If it gets really cold, or they don't provide enough heat, turn them up to high.

You're making it too complicated. KISS, Keep It Simple but don't be Stupid. pipe them conveniently. Just don't series loop them with baseboard.

JP123

Circulator pump

I see many systems that have the circulator pump on the return and the expansion tank mounted directly under the air vent within 12 - 16 inches of the main check valve on the supply manifold. Are these systems incorrect? Also how do you purge the lines with the pump on the supply?



John

JP123

Another idea

Ok, I've attached a revised plan. See if this is viable. I really appreciate everyone's help with this.



John

Gordan

Almost there.

You may need a balancing valve on the return side of the toekick loop. That'll make sure that the addition of that loop doesn't create a low head loss branch that "steals" flow from your existing baseboard loops.



You need to calculate the head loss through your baseboard loops and through the proposed loop. You also need to calculate flow requirements through the three loops. Then you need to find a circulator that will provide the required flow against the total head loss (including common piping/boiler) of the highest loss branch. You'll probably find that you can use the same circ that you've got now, if it's a Taco 007, but you should go through the sizing exercise anyway. Then open up the balancing valve on the highest head loss branch, and dial in the other two to suit your needs.



Not sure what the circulator position has to do with purging - can you explain what's troubling you?

JP123

Thanks

for the reply.



I was wondering about purging with the pump on the supply since it is now "in the purge loop" when purging. By that I mean that when the pump is on the return, the pump is usually downstream of the loop being purged, since the purge pack is usually before the pump. When it is on the supply, it is now between the auto water makeup valve and the purge pack. Won't the pump be restrictive to the flow if it is not running?



John

Gordan

Never seen any Cv specified for pumps while turned off :-)

I can see how this would theoretically be a concern, but in practice, it's not. People who have done a lot more thinking about piping layouts for effective purging than either I or (I presume) you, purge through circulators. It's a very very common thing to do.



Edit: in my previous reply I said that you need to find out the head loss and also the flow requirements for each branch. That was a bit clumsy: flow comes first, then you calculate the head loss through each branch AT the required flow through that branch, and add head loss through common piping AT the required total flow through common piping.

JP123

Thanks

Gordon.



This is all great information. Concerning head loss, how is it calculated?



Thanks in advance,

John

Gordan

Add up all the lengths of pipe, fittings...

Then google pressure drop table for whatever material you've got. It will show head loss per foot of whatever at such-and-such flow.



Installation manuals for your baseboard and toekick heaters should show head loss at different flows, as well.

JP123

Thanks...

for your help Gordon. And thanks to everyone who responded. According to the contractor, it looks like the pump currently in the system will do just fine. The contractor starts tomorrow. I'll be happy when it's all over.



John

Bob Bona_4

where

is the boiler water feed point? That will tell us where to put a central purge station.

You don't need purge stations at each TK, just use a 1/2" baseboard T on each with a coin vent. I put the T on the rear stub so it can be accessed.

It seems like I install at least one K42 every few weeks since forever..I'm always doing kitchen and bath renos :)

I would be itchy to zone this house. And it looks easy enough looking at your sketch.

icesailor

Toekick Install:

I'm not as smart as some here but I don't understand why you would ever want to put two floors and three loops on one zone with one circulator.

I wouldn't on my worst day, ever do this. The first floor would be one zone and the second floor would be another. And depending on the layout of the first floor, that could be two zones. I would need to see a layout of the first floor rooms but I would probably put the whole first floor on one zone but if split, the kick space heaters would probably be mixed with the split parts.

As far as purging, I ALWAYS put a ball valve before the return into the boiler and after the last return connection with a draw off on the return. Something about my old boss and not feeding cold water into a hot boiler. I ALWAYS feed the boiler at the bottom so I can reach the purge by-pass. I purge the whole system from the boiler. I only put Jet Tees on the baseboards to shut up nosey "experts" who gripe about the lack of air vents on the baseboard heaters. I can't remember ever not being able to completely purge from the boiler. On systems I have vented from the baseboards, I still needed to purge from the boiler.

As if it would matter, you have over thought and over engineered this system. A zone valve for upstairs and a zone valve (or two) for downstairs is all you need. Or, all "I" would need.

K.I.S.S.

Keep It Simple but don't be Stupid

(That includes spending cash unnecessarily