72,000 BTU 95% AFUE Natural/Liquid Propane Gas Mobile Home Forced Hot Air Down-Flow Furnace

A:  There is a lot to unpack there and although I can not give you a definitive answer I can tell you how I would approach it if I were called out on a service call. First I would want to know which blower you are referring to as most new furnaces have two; the blower that moves air throughout the duct work and the second blower called a draft inducer that pulls the flue gas/ exhaust through the heat exchanger and into the venting system. The draft inducer should always come on before the unit ignites. After It comes on, the proving switch confirms positive draft and then the ignition cascade proceeds. With most furnaces the blower that moves the air through the duct work comes on later as you do not want to blow cold air. Some furnaces have a control called a fan center and or fan control that allows the blower to come on only when the air reaches a certain temperature. Often these are adjustable. So if that fan is going on and off it could be an adjustment. However many new furnaces use a timer instead. Meaning a control that turns on the blower so many seconds or minutes after ignition. These controls allow the blower to run a certain amount of time after the burner has shut down. So again how I would proceed would depend on which blower I was talking about. However as a general rule "short cycling" is not good for the equipment; reguardless of the efficiency. In fact my 98% efficient unit try's to never shut off. The longer the run time and the less starts and stops the better as you don't get efficient combustion during start up. Short cycling can happen for a lot of reasons. Over sizing the equipment relative to the structure or the heat distribution system can cause this. The thermostat is also a frequent cause. Thermostats can ware or be improperly adjusted so that they turn the heat on and off a too slight of a change. Thus the first thing I do when I trouble shoot a system is take the thermostat out of the equation by jumping it out. By creating a constant call for heat I know the stat is not giving the furnace bad information. This can happen due to worn out batteries or some of the crazy logic built into modern thermostats. Feel free to give me a call if you have further questions. Chris 978 651 3301

A:  I am not sure what you mean by adjustable. Venting codes are extremely strict and vary by state. You would need to speak to a qualified local licensed furnace professional or the code enforcement inspector in your area.

A:  Both are mobile home furnaces so this could be a suitable replacement. However it is not going to be exactly the same. So what you really want to know is this best choice for a replacement. That I can not answer. For that you would want to have the qualified licensed installer on sight with the rough in spec sheet, so that the current installation can be compared with that of the possible new unit. Than they can determine if this would be the best option.

A:  I think its highly likely but it would depend on the venting strategy being used by the contractor as well as the codes in your area. I think it worth noting this is not a chimney vented product. Because of its high efficiency the exhaust is to cool to create draft in the chimney.