(Hup brand, Model 356)

©By: Tim Johnson

Formatted for SOL's Morgan Web by John T. Blair (WA4OHZ)

Originally written: Oct 2005

Last update: dot_clear June 17,2009 - Reformatted page, added installation pictures, corrected email addresses.

My search for information on the heater in my Morgan began when the 12 volt motor quit working. My 1957 Morgan Plus 4 (chassis number 3946) was originally delivered to Fergus Imports, New York from the factory. The chassis record indicates under Remarks: Grey Leather, Wire Wheels. No mention of a heater.

Hup/Maradyne Heater

Heater Mounting and Hoses
I pulled the entire heater out of the car, took it completely apart and could not find a single brand name, model number or any markings except a 1955 date stamp on the motor. I did extensive internet searches, telephoning and finally reached a man who was able to help me. When I described the heater box dimensions and design, he told me I had a Hup brand, Model 356 heater. He also said the color of my heater was the original grey hammertone color. He said, Hup had been sold a number of times, the name discontinued, and was now very similar to a Maradyne, Model 5000. He said Maradyne kept the original design because it was so well done by Hup. I contacted Maradyne by telephone and they confirmed that their model 5000 is the old Hup model 356. (The model 5000 box is square now, not with the older style 356 rounded corners.) They said the replacement fan motor part number was 53005 and they were even able to supply me with a local supplier, who had three motors in stock.

I took all of the heater parts with me when I bought the fan motor. With the exception of having to drill out the two holes to mount the fan motor in the heater box, it was an identical replacement. (The new motor now has a slightly heavier mounting bolt - 1/16 inch diameter larger, but on the same center to center dimensions.)

Heater Installation In Side Of Car
I repainted the heater box with an exact match on color, using Hammerite grey color paint. I also repainted the fan blade, and took the heater core to have it pressure checked. The radiator shop did find a small leak near one of the supply tubes and repaired and painted the core. My heater really needed to be repainted and I was searching for a brand name or model number, so that's why I pulled the heater out of the car. After having removed the entire heater from the car, I found that all of the parts can be serviced or replaced without having to pull the whole heater from the car. To service or change the fan motor, you will need to pull the heater core from the heater first, so you can access the nuts that hold the fan motor in place.

I suspect that the switch which is mounted on the front door of the heater is not original. It is drilled slightly off center, something I doubt that would have been done during manufacturing. I left the switch in place because I like the way it works. It has a "full on" position with a light behind the knob to indicate it is on. A second position puts the switch in to a variable mode, allowing the fan to run at various speeds, with the light dimming or brightening with the speed of the motor.

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