Polaris used for radiant heating & domestic hot water.

daneheat

Had a not heat call begining of the week. Found a Polairs water heater that was used for radiant heating. 

The unit was installed by the home owner, 3 years ago.Bought it off the internet. Said it was working fine until now. The combustion chamber was full of water. First thought was that the unit was leaking. Took the water out of the combustion chamber, could not find a leak. We had a heavy wet snow, thought that may have been the source and he had a trap in the fresh air intake. Went under a beam and then back up. Drilled a hole in the trapped area, which was dry. Where did the water come from? Called American and they said it must be leaking and they would send a new unit under warranty.  Dan, our son said he did not under stand the piping, didn't see how it could work.  There are two tappings for the coil on the side of the heater, but they were not being used, it appeared that he was using the domestic hot water to heat the house. After the new heater arrived, Dan & Bill removed the old unit and installed the new heater, installing an air scope, expansion with auto fill, the works, as it should be with a gas water heater with a heating coil. Put a tempering valve on the top of the heater as we usually do. Turned on the water a found that there is no coil in the Polairs heater, What looks like a coil is the internal gas heat exchanger,  The way we have it hooked up it is working fine. Removed the auto fill and expansion tank, as there is no check valve going back to the water supply. The owner, wants to know why we changed the piping from what he had. We thought the unit had a separate heating coil. We could put in a separate heat exchanger and isolate the heating from the plumbing. This is the way most direct water heaters are set. Not the polaris. The way he had it connected there was always fresh hot water going into the heating system and then to his hot water faucet. The way we have it now there will be no fresh water going into the heating system, when the system is dormat in the summer.  I am thinking of going back and changing it back to the way he had it piped. What are your opinions, are there code issues either way?

Where did the water come from to flood the combustion.  While we were working, they ran water down the main drain and the floor drains backed up and also the main stack was filled.  The condensate drain was laying on the floor and water started coming out of it.  We traced the condensate drain to a tapping into the 4" brass cleanout in the plumbing stack.  It's life great.  When you think you have it all figured out, stand back, you don't.  What to do?



Need suggestions.  Dan  

   

Steve Whitbeck

Danger

The way you have it piped is VERY dangerous. You are in danger of legeonairs (sp) disease.

You need to install a plate and frame heat exchanger between the water heater and the heating loop. You will need another pump also.

This can kill your customer and you will be in a LOT of trouble.

daneheat

Polaris water heater

We are changing it back to the way it was piped before.

Steve Whitbeck

NO NO NO

That is not good enough - You need to install the heat exchanger and pump. It doesn't matter where on the tank you tap the hot water off of - it is still domestic hot water. If you don't repipe it properly YOU better have a LAWYER draw up a release form and have the customer sign it. OH and double your insurance - YOU may need it.

ewp

Wait a minute. That might be a bit much:

The above poster is half right and half wrong. It might be to late now, but you will not kill your client by returning it to open direct configuration. He is correct that you need to change the system back to the way it was plumbed previously. And it needs to be done correctly. You do not need the extra expense of the pump and exchanger.



The best drawings for all of this are on the radiantec.com website. I am not related or connected to them at all but they have a lot of information.



You are at risk of legeonairs if you have stagnant heat piping in the summer. The system that was installed is an open direct system that is code approved and pretty smart. Saves a lot of extra parts and pieces. The trick is that you must have cold water entering your heating system even in the summer and then traveling to the hot water heater. In the winter you have a slight loss of heat as cold enters the floor (mass of your radiant absorbs this) and in the summer you get a pre heating and cooling effect as the water absorbs heat from the slab. Check out the diagrams on the web site. We install these systems all the time in Utah and have has great success.



Not the best for non slab heating applications but fantastic for slab radiant heat.



Eric

Mark Eatherton

OK Eric, I'll bite...

Tell me HOW you can make one of these systems TOTALLY safe under ALL conditions, and I might buy into your theory.



I'm listening with open ears and an open mind. Please shine the light and show me your way.



ME

gennady

polaris

Steve , you are absolutely right in my opinion. Also i think plate heat exchanger is needed not for heating, but for domestic hot water. slant fin combi cat is just right for the job. Has build in circulator, activated by DHW flow sensor.



https://docs.google.com/viewer?url=http%3A%2F%2Fwww.slantfin.com%2Fimages%2Fstories%2FProduct-Literature%2Fcatalogsheet_dhwg_10a_dhwg-10a.pdf

Steve Whitbeck

ERIC

The original and any other piping configuration that does NOT use a heat exchanger will not pass codes. No mech inspector here would pass your system.

Tim P._3

it's permitted in most areas..

Not that I would ever recommend such an installation, but the IRC permits it.  I am sure some areas don't use the IRC and others have amended it out, but it's permitted by default.



Tim







SECTION M2004 WATER HEATERS USED FOR SPACE HEATING







M2004.1 General. Water heaters used to supply both

potable hot water and hot water for space heating shall be installed in

accordance with this chapter, Chapter 24, Chapter 28 and the manufacturer's installation instructions.

Henry

Combo heating

We have several thousand combo hot water tanks that supply domestic hot water and heat in our case, baseboards. The gas utility promoted this type of system as a replacement for central wall heaters to keep electrical baseboard heating out. I got a patent for making them functional during power failures.

The trick to making them safe during the summer months is, to makes sure the pump on the heating side run for a few minutes very day. It is so noted in the certified instruction manual of the hot water tank. Also, the tank must be certified for combo heating. Most of the certified tanks will have duplicate tappings, one set for DHW and the other for heating.



I have not checked the Polaris but if you checked the certified I & O manual, you would have instructions on how to pipe the unit for combo heating. BTW, a drowned combustion chamber may not be a sign that it is leaking. We have had several Bradford/White and one A.O. Smith Cyclone that were full of water. It is usualy caused by a blocked neutraliser or an acumulation of scum that partialy blocks the combustion chamber. We make our own neutriliser with a rubbermaid container and terrazo stone. It never blocks! As for the blocked combustion chamber, one needs to remove the burner and pass the shop vac to clear it.