Heater upgrade: Maradyne to HeaterCraft, 9" to 16"

[Upnorth07]

My 2020 XT22 came with the factory heater option which is a 9" heater unit by Maradyne. It features four, 2" outlets and supposedly puts out about 28,000 BTU. My dual screen dash is wired for high or low fan speed outputs. The fan volume was fine but I was looking for more heat output as we boat in cool waters and sometimes late evenings and the family enjoys the cabin heat.

After researching higher BTU units from both Maradyne and HeaterCraft, I purchased a HeaterCraft 340 Elite Unit directly from HeaterCraft (they had better customer service and answered a lot of questions for me). Essentially, I went from a 9" unit to a 16" unit which is essentially a larger radiator unit. I finally got it installed and tested after it took 60 days for delivery!

The HC unit has 4, 3" outlets so I had to buy some 3" to 2" reducers which I got off Amazon. They are silicon turbo piping reducers (queue Fast & Furious).

I carefully cut off the factory electrical connector from the Maradyne unit and skillfully integrated it into the HC wire harness so everything is plug and play and looks factory. Both fans (Maradyne & HC) are wired for high, medium, and low but the output from the boat is only one hot wire and a ground. The boat only has high and low settings and must control the amperage? through the hot lead telling the fan to be in high or low mode. I wired the HC fan to the "high" setting but both high and low through my screen work.

I've only had the boat out for a 10 minute pre-season shakedown run and there was heat, but I have not done a full family assessment yet but so far, things look good.

First pic is of the factory Maradyne unit.

My factory MasterCraft/Maradyne unit is now for sale.

[Upnorth07]

More pics

[Wakejunkie]

Nice post and update. I’m curious on the amperage draw for fans on new unit. I know the pdm has programmed values to operate. Hopefully it all works as normal within the range. Post some completed installation pics

[eecyclone]

Nice upgrade! Let us know about the heat output increase. I was thinking about making the same upgrade.

Aren't the orange and red wires both hot for either the High or Low setting on the screen? With the black wire for ground?

[Diesel]

Nice post and update. I’m curious on the amperage draw for fans on new unit. I know the pdm has programmed values to operate. Hopefully it all works as normal within the range. Post some completed installation pics

I added the same Heater Craft unit to my X24 and so far no issues with the PDM. Do note you completely bypass the Heater Craft fan speed resistor and hook the PDM heater output wired directly to the motor. The PDM drops the voltage for Low fan speed.

[Diesel]

Aren't the orange and red wires both hot for either the High or Low setting on the screen? With the black wire for ground?

The PDM only outputs Red+ and Black - for the heater circuit. So even though the OP kept the other colors in there, it's only the orange and black that he is using.

Also to the OP, you can remove the orange jumper and just hook the orange wired from the PDM directly to the motor if you want. It will work the same, but just removes an unnecessary jumper.

[eecyclone]

The PDM only outputs Red+ and Black - for the heater circuit. So even though the OP kept the other colors in there, it's only the orange and black that he is using.

Also to the OP, you can remove the orange jumper and just hook the orange wired from the PDM directly to the motor if you want. It will work the same, but just removes an unnecessary jumper.

Thanks for the info. I thought I saw both high and low wires in my '18 but haven't looked that closely.

[Diesel]

Thanks for the info. I thought I saw both high and low wires in my '18 but haven't looked that closely.

My 15 x23 had both low and high wires and I was a bit confused when I started my install on the x24 because it only had a red and black. Somewhere along the line they changed it to the PDM dropping voltage - probably when they eliminated all manual switches and went to full screen control. On mine, IIRC low is 7.5v and high is full 12v.

[Upnorth07]

The PDM only outputs Red+ and Black - for the heater circuit. So even though the OP kept the other colors in there, it's only the orange and black that he is using.

Also to the OP, you can remove the orange jumper and just hook the orange wired from the PDM directly to the motor if you want. It will work the same, but just removes an unnecessary jumper.

Yes, the orange "+" carries the both voltages, high and low. Instead of cutting into the boat side of the heater wire harness, I left it all stock/factory using the factory connector, knowing I only needed the one "+" wire and the black ground.

Overall, the install was pretty simple and straightforward.

[barneyferd]

Very nice write up. I’m definitely am doing this one.

[MCOR]

OP wondering if you noticed a difference in BTU output with your upgrade.

[Upnorth07]

Yes, heat output is better but not necessarily overwhelmingly hot. The financial investment was about $430 and I was able to sell the factory Maradyne unit for $200 so net cost $230. To me, it was well worth it and I got to know my boat systems better through the installation and closed cooling (GDI) piping.

[Wakejunkie]

Yes, heat output is better but not necessarily overwhelmingly hot. The financial investment was about $430 and I was able to sell the factory Maradyne unit for $200 so net cost $230. To me, it was well worth it and I got to know my boat systems better through the installation and closed cooling (GDI) piping.

Planning to add this heater to my XT22 soon. I don’t currently have a heater so I will need to add coolant lines and drill holes for vents. Can you provide details on the coolant mine routing? I know factory is 2 fixed vents and 2 pull outs. Would you have 4 pull outs if building it yourself?

[maniacmikes]

Planning to add this heater to my XT22 soon. I don’t currently have a heater so I will need to add coolant lines and drill holes for vents. Can you provide details on the coolant mine routing? I know factory is 2 fixed vents and 2 pull outs. Would you have 4 pull outs if building it yourself?

If I was doing it from scratch, I would strongly entertain the idea of adding two small heater cores rather than 1 big one. The closer the heater core is to the point of use, the hotter it is going to be. That's why the drivers foot heater outlet is always pretty hot, while the rest of the boat heater outlets are just luke warm.

The local custom wood boat making shop (who is also the MC dealer) runs ilmore closed cooling systems and they run up to 4 heater cores in their boats, so I know the cooling system can handle it. They told me if I was going to do two heater cores, to just wye off the main line and run it to each core.

I personally think the pull-out heaters are the only way to go. The fixed ones are pretty useless, maybe because they are not very warm, maybe because of the locations... but in general you just have to be super close to the heater outlet, or have it tucked under a blanket/shirt to really feel it does any good.

I have not scouted out the best locations for the heater outlets, and I am sure it depends on the boat... but I would put two outlets up by the driver- one blowing on the driver, one accessible to the observer seat. Both pullouts. Then I would put a second heater core around where the cooler is (or opposite of that by the coffin seat) which would service the main cabin. Again, two outlets, both of them pullouts.

[Wakejunkie]

If I was doing it from scratch, I would strongly entertain the idea of adding two small heater cores rather than 1 big one. The closer the heater core is to the point of use, the hotter it is going to be. That's why the drivers foot heater outlet is always pretty hot, while the rest of the boat heater outlets are just luke warm.

The local custom wood boat making shop (who is also the MC dealer) runs ilmore closed cooling systems and they run up to 4 heater cores in their boats, so I know the cooling system can handle it. They told me if I was going to do two heater cores, to just wye off the main line and run it to each core.

I personally think the pull-out heaters are the only way to go. The fixed ones are pretty useless, maybe because they are not very warm, maybe because of the locations... but in general you just have to be super close to the heater outlet, or have it tucked under a blanket/shirt to really feel it does any good.

I have not scouted out the best locations for the heater outlets, and I am sure it depends on the boat... but I would put two outlets up by the driver- one blowing on the driver, one accessible to the observer seat. Both pullouts. Then I would put a second heater core around where the cooler is (or opposite of that by the coffin seat) which would service the main cabin. Again, two outlets, both of them pullouts.

Interesting info. I was curious how much heat would be lost from stock location to passenger side with that run of ducting. I thought about using insulated 4” ductwork. The twin heaters isn’t a bad idea. Problem for heater location on passenger side in the XT22 is there isn’t much room unless you take away storage. I was thinking 3 pull out euro louver by maradyne and 1 fixed at drivers helm. 1 driver side pull out in stock location and two pull out on observer seat.