Albiemanmike
Well-known member
Been a while since I have posted anything life always seems to get in the way. Anyhoo I have a Modine Hot Dawg Model#: HD75AH0134 which seems to be an older model based on several things. This heater has worked perfectly in my large garage since we moved in in 2013. But last weekend I noticed it was cold in the garage and attempted to turn the heater on but got nada? So I pulled the side cover and started troubleshooting. This model does not have any LED diag lights and only has one circuit board which seems to be nothing more than distribution point for all the connections. I checked the thermostat to make sure it was clicking on etc. asking for heat. Then I checked for 120VAC at the heater both checked good. So next move was to check 24VAC off the secondary of the transformer and that checked bad? According to the newer Modine troubleshooting guide that pointed to a bad transformer.
So I ordered and installed a new transformer and that had no affect on the situation? So I started checking different points in the heater for voltage trying to see if I found anything that seemed out of the norm. I unplugged the gas valve and checked the secondary on the transformer and got a reading of 13VAC which it should be 24VAC?
I called Modine but they don't deal with end users and only told me to contact an HVAC company nearby. I don't mind doing that really but #1 we just had an HVAC company come by to look at our house furnace and they said our problem is that the furnace is too big for the house, which it is after doing a little research, and that we don't have enough return air which also I confirmed. I asked him for a quote on adding additional return air to the system and never received a call back or visit? That is why I try to do most everything myself because it is infuriating dealing with these so called "experts". I have electrical training from the military and worked as a dealership technician for Mercedes/Porsche/Ford and this piece of equipment isn't nearly as complicated as those vehicles were. But I don't have schematics or OEM manuals other than what I found online. I hate throwing money/parts at something so I was hoping someone here might have some HVAC experience that could give me some tips or guidance on what to test etc. in order to figure out what part I need to replace? Thanks again for your input/advice this place always seems to be the go to.
So I ordered and installed a new transformer and that had no affect on the situation? So I started checking different points in the heater for voltage trying to see if I found anything that seemed out of the norm. I unplugged the gas valve and checked the secondary on the transformer and got a reading of 13VAC which it should be 24VAC?
I called Modine but they don't deal with end users and only told me to contact an HVAC company nearby. I don't mind doing that really but #1 we just had an HVAC company come by to look at our house furnace and they said our problem is that the furnace is too big for the house, which it is after doing a little research, and that we don't have enough return air which also I confirmed. I asked him for a quote on adding additional return air to the system and never received a call back or visit? That is why I try to do most everything myself because it is infuriating dealing with these so called "experts". I have electrical training from the military and worked as a dealership technician for Mercedes/Porsche/Ford and this piece of equipment isn't nearly as complicated as those vehicles were. But I don't have schematics or OEM manuals other than what I found online. I hate throwing money/parts at something so I was hoping someone here might have some HVAC experience that could give me some tips or guidance on what to test etc. in order to figure out what part I need to replace? Thanks again for your input/advice this place always seems to be the go to.