Contradictions

Randy_9

I have recently run PEX for my kitchen floor during a remodel. The design was completed by an RPA member and is setup for 2 runs with a water temp of 115 degrees. Since the rest of the house is on baseboard (2 zones), I figured the best way to run the system was with a primary/secoindary piping setup. John Siegenthaler makes a compelling case and I have received great input here. However, when I called my boiler company to help hook it up, they were lukewarm to the prospect of piping it that way. Is there more than one way to skin a cat here? They are more familiar with a different setup (circ. on the return) and I thought that pumping away and using P/S was more efficient and better for the boiler. Now, I have radiant in the floor, baseboard on the walls (which needs to come out) and a wife who isn't happy. Which way to go?
Radiant pics are attached, plates on top of subfloor in plywood sleepers with 1/8" covering before the finish floor goes down.

Randy

Justin Gavin

Input

What kind of boiler is it?

Also, how are you going to control the temp of the water in the kitchen.

How is the system piped now? (Contnuous loop?)

If so here's a thought.

First move the pump to the point of no pressure change even if it is in the same loop as the existing baseboard loop.

At the return to the boiler (after all of the radiation) put in a set of close set t's. on the firs T bring out a line and pipe into a mixing valve. Than add a small circulator with integral check and connect to ths supply manifold of your radiant. Than from the return side pipe first to the mixing valve with another T and follow on to the 2nd T on your close set t's (on the return). On the T's before the mixing vavle put ball valves to isolate this "zone". Also you might try the Taco ZF series pump. It has a relay built into the pump so you run the pump off of its own tstat.

If you do this you will still be "pumping away" and you won't have alot of extra piping.

Food for thought on the circ pump for the radian make sure you use isolation valves with purge valves. And after the supply manifold and before the mixing valve put in a hose bib followed by a ball valve.

This will help when you want to purge the air out of the new loop. Also if you don't already have
Make sure you have isolation valves on the returns of your pex connections.

Good Luck,
Justin

hr

Hard to say

without seeing their method

The PS arrangement brings many pluses as you probably are aware. You need to protect the boiler from extended run periods of low return temperatures, in the radiant mode, and be able to mix down the output temperatures. If you are using a convential boiler.

If this, and assurance of proper flow rates, ghost flow prevention, and adequate air removal are all addressed in his method...


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Randy_9

I understand there are significant vagaries with this question. I am not exactly sure of their method. I would need a schematic. I am trying to decide if I pursue my choice based on my understnding of the issue, or if I tell my heating company, who does this for a living, how to pipe my system. It is a very fine line to walk. It makes you feel very presumptious to tell someone else how to do their job.

That aside, it is a conventional Burnham. The circ. currently resides on the return. My thought was to disconnect that circ.(a Taco 007) and move it past the exp. tank for the primary loop-1 in. pipe. The baseboard would be the first secondary- another 007 feeding two zones of baseboard, each about 65 ft. of fins, with zone valves on their respective returns before they join for a common return to the primary on a closely spaced tee. The radiant is the next secondary with a thermosatatic mix valve (100-140) then a 008 circ. then the radiant manifold. The return tees into the cold of the TMV and back to the primary loop. I would put check valves on the returns(?) of the secondarys and all circs controlled by a Taco relay.

Randy