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Need HELP with new sys.

:confused:I have built a new shop and put pex in the floor for heat. 600sqft. with 600 ft. of 1/2 tube. I was told that I could use a hot water heater for boiler and use as hot water for sink. Now I find out that is not the best thing to do, so I have the wrong pex in the floor, was told that is OK use all brass or copper and that is OK. That is what I will do. Now know :confused:one will help me make up a sys. I want to use a Takagi jr. heater,I thank all I need with this is are Sprovent jr. air eliminator valve, Expansion tank [2gal],1/25hp bronze pump, back flow preventer, pump relay for stat,T&P relief. I have read all I can Find on this stuff I have done a lot of plumbing and remolding and I think I can do this if someone will give me some answers.

Re: Need HELP with new sys.

It's not clear from your post what equipment you already have, aside from the PEX---I don't see any problem using the PEX for the project.

Who told you it wasn't allowed??

The company below (radiant company) has a free installation manual for takagi jr. systems (no obligation to buy anything).

They also have a lot of info and assembled parts (kits) that are designed to work with the takagi jr.

There are also other companies on the internet & locally that sell parts and kits for the system you have in mind.

Google "takagi jr radiant floor heat" (without the quotes) for numerous links on this topic.

Some local ordinances don't allow the use of the same water for the heating system and for domestic hot water use.


Re: Need HELP with new sys.

As I recall, PEX was developed for use in hydronic heating systems. It's acceptance for potable water use came later.

I wouldn't recommend using brass fittings in a slab; it seems the concrete would corrode the fittings. However, if the fittings are certified by the manufacturer for embedding in concrete, then it's OK. I suspect some jurisdictions might not permit in-slab connections; a continuous run of PEX may be required. If you mix & match brands of PEX & fittings, the manufacturers may not honor their warranties. It's best to stick with one brand for this reason.

PEX is PEX -- it shouldn't matter what "kind" is used. Your best source of information will be from the manufacturer. Don't depend on friends, acquaintances, or even the posts on this board for qualified advice.

Re: Need HELP with new sys.

Please explain what you mean when you say you were told this was not the best thing to do.
Although open systems like you described are allowed is some jurisdictions they are not allowed everywhere. Some jurisdictions require the heating system to be a closed system. The big advantages of a closed system are that you can add antifreeze and it is separated from the potable water supply.

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