Recent content by classic

I use a Rinnai 94% afue hot water heater with a hot water coil in my air handler. For heating a Grundfos circulator pump to push water to the coil the return goes back thru the Rinnia unit. For domestic needs a mixing valve brings the water down to 120* 200,000 btu, can be used with multiple...

This is a situation that you need a professional evaluation - you need what the business referrs to as a Manual J heat gain-loss calculation. The furnace deals with the heating (heat loss) side, while the heat gain refers to the cooling requirements. It takes in account insulation, windows...

If the coil gets blocked up every summer you might want to try a 4 to 1 mixture of lemon flovored clorox and water into the drain pan each summer. This will kill any residual mold in the pan and lines. you know the pan is going to clog at least once, so be proactive and plan on cleaning the...

You need to find out why the filters were wet in the first place. There is no reason for moisture getting into the return ductwork. There must be some air leakage in the return side for water to get into the system.

Slove the problem first! Where is the dust comming from in the first place? A proper HVAC system is a closed system - air is pulled across the filter where it is cleaned, goes to the unit where it is heated or cooled, then comes out the supply registers and into the house. Then, it goes...

An excellent rule of thumb for return sizing is filter length x filter width x 2 = capacity, so 20 x 25 x 2 = 1000 cfm and 18 x 18 x 2 = 648. You have a nominal capacity of 1648 cfm and a 5 ton unit needs 2000, so you are 20% undersized. Your real problem is heat trandfer 101 - hot are rises...

Just because you charged and old unit in spring does not mean it is still charged properly. Does the air velocity still feel the same?

if this is loose insulation in an unlined return, the return suction pressure has pulled the insulation in from the attic or walls. This means that your return trunk is not airtight and your efficiency has dropped. Vacuum the insulation out. Seal it if possible If it is blanket type...

Assume that you have a 2 1/2 ton air handler that moves 1000 cfm of air. Now assume that you are loosing 20% (200 cfm) of this air under the house thru duct leakage. 1000 cfm is being sucked into return but only 800 goes back in, so the house is in a negative pressure situation. Open the...

1) if oil filter gasket is not 100% tight air can get into the line and shut it down 2) same for all oil piping connections 3) cad cell could be getting weak 4) dirty/blocked oil filter