not enough heat in house open system empyre

[bobjack]

have open system empyre outdoor boiler going into forced air system. no trouble last two years heating house, this year can't get above 70F on a 25F day. Water temp at 180F. previous years, water line going into heat exchanger in forced air furance was hot, and return line coming out much cooler. Now we check and feel the lines are both very hot. Would think if heat is being removed the return line should be cooler. Did try putting on new circ. pump, made no difference. Fan for furnace is running. could air in lines somehow be a problem? any suggestions appreciated. by the way, our HVAC installer placed the radiator in the cold air return due to problems with space, so air is drawn thru rather than blown over radiator. system worked last two years, don't know why this would cause problem now, but????

 

[RJP Electric]

I am no HVAC guy, but being in the return plenum before the filter do you think it got clogged?

 

[bobjack]

we checked, not problem. thanks

 

[wtom24]

If the supply and return water are hot, that signals lack of heat transfer in the coil to the air. Try measuring the discharge temperature. Your airflow may be low due to clogged filters or some other reason.

 

[heaterman]

You have an air flow problem. If the issue was with the water circulation (as in not enough flow) you would see a very large temp differential from inlet to outlet of the HX coil. Seeing as how you have nearly the same temp in and out, that would indicate little to no airflow across the HX. Start upstairs by checking all the cold air returns in the house to see if there's a rug over top of one, furniture blocking them, registers closed etc. Then work your way down to the furnace. Air filter, slipping or broken belt, worn pulleys, something blocking the blower wheel........all of them could be your problem. I had a guy call me up a couple years ago saying that his furnace wasn't heating right anymore. This was on a 5* day with about a 25mph wind blowing. Came to find out he had replaced the direct drive blower motor on his furnace earlier that winter not knowing that the new motor was reversible rotation. He had never checked it out and the thing had been running the blower wheel backward for 2 months. A blower will actually move a bit of air in that circumstance but probably less than 20% of normal output. Check it all. It has to be in the airflow.

 

[heaterman]

I'm curious as to whether you figured your problem out? If so, what was it?