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[rsv101]

Any ideas would be great. I have a Johnson outdoor wood burner.  All pipe coming from stove to house is new and insulated well in last 2 years. I have a 50 plate flat plate heat exchanger that was put in at the same time.  I am getting great heat to the house.  It is pumped to the house with a bell and gossett pl-36 pump.  On the house side I have a viessmann gas boiler and viessmann 53 gallon water storage tank.  I dont seem to have good heat on house side.  I have baseboard hot water, it is all on one zone and is approx 2000 square foot on the zone with 15 baseboards. Even when I am not calling for heat I cannot produce enough hot water from the wood burner to recover my domestic hot water even though the hot water coming into the house is 160.  It will take hours for the wood stove to recover the domestic hot water tank. The domestic hot water zone and baseboard hot water zone are both on seperate zone pumps and each pump is a taco 007-F5.  My baseboards never truly get hot even after running for hours. I am kind of thinking flow is not enough and i am wondering if a bigger pumps would help and what kind? This system was in the house when i moved there and i have been trying to improve it. Any ideas or suggestions would be much appreciated.

[slimjim]

Sounds to me that either your circ on the gas boiler has quit or it is airlocked

[rsv101]

The water does not circulate on the house side until the system is calling for heat or domestic hot water. Both domestic hot water and baseboard taco 007-f5 pumps are new.  On the house side there is good pressure in the system and air has been bled.

[slimjim]

I would say that they are not plumbed properly or you have 2 bad flow checks and that is highly unlikely, could you draw us a picture of how it's plumbed?

[rsv101]

Thank you for your input, please see attachment for diagram of layout.

[slimjim]

Ok I'm not seeing anything stopping the circs from pulling water through the gas boiler instead of the plate exchanger!

[rsv101]

I have the ability to shut the boiler off so it does not fire and the water just can then move through it. Which i have shut it down but it just takes forever for the dhw water to recover.

[rsv101]

On the house side of the flat plate exchanger when either pump is running the pipes are not very warm. You can grab any pump and hold it no problem

[hondaracer2oo4]

Clogged or airlocked plate exchanger.

[rsv101]

i did isolate the short loop of the exchanger on the house side , about 4 feet on both hot and cold and drain and refill the short loop. Water drained clean. I did that twice.

[slimjim]

That will work but there is a better way, if you give me the evening I'll post a drawing of what I would do because your gas boiler is a cold start unit and should not need to be heated!

[rsv101]

I have attached some real photos of my system.

[slimjim]

I truly hate to say it but whomever put that together should try again because it ain't right, I'll be home in about an hour and try to draw something up for you! I think your issue is that the water from your zones is going through the gas boiler and not the plate exchanger, let me guess if you are burning gas all works fine right?

[slimjim]

OK the wife has had me doing THE honey dew list, look at your original drawing, as I see it the plate exchanger has more resistance than the boiler loop, really look at the piping and determine if the circs might be pulling water through the gas boiler instead of the plate exchanger, remember , water will always take the path of least resistance, can you close a ball valve on the gas boiler loop to stop the flow there? if you can and then the system works OK then it needs to be re plumbed, I suspect that the water on your loops is simply flowing through the gas boiler and not the heat exchanger, there are several ways to fix it!

[rsv101]

Ok my thought is to plumb the hot line from the flat plate heat exchanger into the return line of the gas boiler and plumb the return cold line from the baseboard and domestic water into the cold of the flat plate exchanger. That way the water is hot going into the boiler and coming out hot. I am thinking that should help with proper flow and i can shut the gas off and just let the water flow through the boiler, then when summer comes isolate the plate exchanger and turn the gas on for domestic hot water.

Do you think the taco 007-f5 pumps are the proper pumps for the job?

At one point someone had a pump running 24-7 on the house side it is now gutted, would it be necessary to have water flowing on the house side if nothing is calling for heat?

Should the hot water coming from the wood stove be about the same temp as the water coming out of the hot side of the flat plate heat exchanger?

Thanks for the help again!