H-120 ASH Fix-up Thread

[CallMeColt]

Everyone,

Got myself a H-120 Army Space heater this morning from the auction yard. Got it for a real good price so figured I'd get it while I was there for other things.

Has less than 3 hours on it.

Tires were horrible, but I had some to swap on at the house. Will do something better if I get it working 100%. Has the long exhaust pipe with it, but not the elbow. Had a remote inside but it was for a H-140 after doing some reading. Guess that will go on the eBay store to recoup some money into getting this thing going. Got two of the ducts with it as well. One vent cover and screen is missing. Broke one bolt trying to remove it from the exhaust pipe cover. Not sure, but I think something is broken with the Thermostat breaker.



Put 3 gallons of fuel in and cut the Amphenol connector off of the 110v power connector. Made a temporary connection and moved the switch to vent and we have a blower! Power light does not come on.

Held the purge switch for a while. Hard to tell if it was working. The gauge never moved... it could be bad, or no fuel is moving?

Got the Flame Out light. Kept resetting and purging, no luck. Nothing seemed to be going on in the sight glass. From the directions, there should be an ark or spark if there's no flame?

Confirmed fuel is pumping by checking the fuel filter. Found it had been removed. Need to figure out that part number as the one in the TM comes up with nothing.

My guess from looking at the diagram, was that the transformer for the ignition is bad. I also need to order some of the bulbs for the power light as I'd guess it's bad. May swap with the Fire Out to see quick. Want to see this thing make some heat before I go to wild with it. Though, I'm sure it will get going.

Any help in finding downloadable TM's would be great. I will then share them in the uploads section.

 

[CallMeColt]

Spent some more time with it yesterday.

After looking it over with a bit more light, I found the elbow. Was happy about that. Noticed a few bolts missing on the part of the burner (not an HVAC guy, not sure the proper name) and decided to open it up because that meant someone was in there at some point.

Sure enough, found that the two connections to what my guess was where the spark is made were pulled off and set to ark out on each other and were doing just that.



Hooked them back up and cleaned out some of the dead grass that managed to get in there. Rigged up a plug again and gave it a rip. Fired up!



After about 20 minuets, the heavy smoke cleaned out. Old fuel in the lines and the other crap in there burnt off. Was getting about 140deg output. After a while, the High Heat would shut it off... it is still in the 80's here in the afternoons right now. Let it cool and ran it another 30 minuet cycle.

While it was cooling down, I installed the outlet for the 110v power I ordered. Amazon showed up just in time.

SEEBOO 15 Amp Flanged Inlet 125V



This gets rid of the cord to trip over and silly Amphenol connector. I will make an extension cord and store it on the unit along with a couple hand tools as I like to keep the basic things needed for stuff like this right on the unit because we all know when you go to use it, setup time is usually urgent and running around looking for things is annoying. had to drill a 2 1/8 to the side of the existing one, then just taped the old one off. Could do it better down the road but it works for now.

Remote thermostat should be here soon, and I am going to order some bulbs as I did move over one to the power and it lit up... that bulb was blown.

The exaust extention was a little bent but fiddled with it and did get it to fit on the elbow. Would like it all to fit and seal better but in due time.

The fuel filter is nowhere to be found for this, so I am going to change it to something more common. I have one I like that is cheap and I have changed it out to be used on my Kubota tractor. It is used on the MEP-831A. I am going to change over my MEP-802A generators to them as well.

Fuel Water Separator

Last thing I would like to figure out is the fuel pressure gauge. Getting no impact, no idea on the part number with the TM. I don't need to have it but my OCD likes to have everything working 100%.

I'd also like to make the external fuel connection the same as the AN-5 fittings that are on the generators, so I could use the same hoses as I do for them for extended running. The one that is on these is strange.

Thanks for following along. Any help or input would be great. For the cost, this will be a good unit to keep around in case it gets real cold... we are not used to that here. Certainly, will not need to worry about working in a cold garage anymore in the winter months!

Oh, and a member here needed that controller for their H-140, so I'll be selling it to them.

 

[Guyfang]

What TM number?

 

[CallMeColt]

What TM number?

TM 9-4520-258-14 is the one I am missing. I have TM 9-4520-258-24P. Those are on the unit.

I think a new TM superseded it though, TM 9-4520-258-13&P.

 

[CallMeColt]

So without the TM, I'm unsure how to wire the remote thermostat that I got today! There are 3 wires. I was going to guess they'd match the markings as they usually do... A, B, C as on the connector and wires on the unit itself.

Inside the thermostat is 1, 2, 3. 1-A, 2-B, 3-C is my best guess, but I don't know if I want to take a chance hooking it up incorrectly and damaging the thermostat. I got the last one the seller had & I stumbled upon it for sale by chance. Doubt I will find another.

Otherwise, thing is running good. I also got proper wheels for it but in a solid version. Got a cap for the exhaust that works well. Found an HVAC supplier that had 12 inch end caps for cheaper than Home Depot so I have one on it's way to cap the supply side when not in use.

Looking through the parts TM, there is supposed to be a gasket on the end of the burner I took off. Going to find some of the material that is says is used to make that out of to make that right.

Anyone who comes up with the TM is my hero! Or, if you by chance have one of these with the remote thermostat, quickly checking for me on what is what will help me wrap this project up. I'll send you a few bucks even... time is money!

 

[CallMeColt]

Okay, so I had to come here to complain... I found the information I needed. The file was on a clickbait site but I managed to get the information I needed. Couldn't extract the whole TM from there.

 

[CallMeColt]

I wired to thermostat up temporarily while I'm waiting for a new set of connectors to come in. It gets power and does what it is supposed too. Burner doesn't want to start though, even when I put the remote in "HI".

Looking at the wire diagram, I think it is the S3 switch that may be bad. It's been exposed to the weather for who knows how long. My issue is, finding that part now. I'm not an HVAC guy, so learning what the numbers mean is taking me a bit. The TM has it as part # 20600D39-153. It is a L-160-2 temperature range switch I guess. The other switch is the high temperature, part # 20601 L8-276. Unless they were mixed up or changed out at some point, but I don't think so. I'd honestly just like to change both out as I can't see these being costly parts.

 

[CallMeColt]

Alright, so... in my over thinking, I completely forgot there is a wire diagram right on the unit under to cover for the controls.

Anyways, in looking at it a bunch of times and scratching my head, I realized when I wrote down what wire goes where, I crossed wire colors in the thermostat remote itself. So, swapped them and it started working as it should have. Yikes.

Anyways, at least I got that figured out! Connector should be here today. Hope to have this thing 100% by weeks end.

 

[Guyfang]

Uploaded the TM's for the heater into the misc. TM's forum.

 

[CallMeColt]

Uploaded the TM's for the heater into the misc. TM's forum.

Will go look now, thank you!!

 

[CallMeColt]

Connector came in and I got the thermostat remote all setup as it should be so that it is removable.

A few more small parts are on their way. Once I get it 100%, I will probably make a video about it since there are none out there to my knowledge, showing how exactly it works and stuff. Definitely a neat unit to have. I could imagine folks up north would benefit from one way more.

 

[CallMeColt]

Made the missing cover fit that came in. Last thing, is the fuel filter and fuel pressure gauge. The gauge I got will fit but I found in the TM that the pressure goes higher than the range I got. Not sure if I will install it. Finding something to replace it is seeming to be hard. I'm wondering if switching to an electric one with a transducer will work out better? Hmmm.

 

[Guyfang]

Made the missing cover fit that came in. Last thing, is the fuel filter and fuel pressure gauge. The gauge I got will fit but I found in the TM that the pressure goes higher than the range I got. Not sure if I will install it. Finding something to replace it is seeming to be hard. I'm wondering if switching to an electric one with a transducer will work out better? Hmmm.

Perhaps if you published this data, someone here might be able to help.

 

[CallMeColt]

It is a 0-200 PSI Fuel pressure gauge, part number G32781. NSN 6685-01-399-0065. NSN information really doesn't seem correct as it comes up with temperature information.

 

[CallMeColt]

Here is the overview video I said I was going to make;

 

[Guyfang]

It is a 0-200 PSI Fuel pressure gauge, part number G32781. NSN 6685-01-399-0065. NSN information really doesn't seem correct as it comes up with temperature information.

Try 6685-01-496-9994. The other NSN is canceled.

 

[CallMeColt]

Try 6685-01-496-9994. The other NSN is canceled.

Amazing! Found one. Got it on it's way.

 

[CallMeColt]

So, installed the new gauge today. Old one had a ton of rust come from behind it.



It isn't a direct replacement, even though it is a NSN replacement.



New one has NPT, the old one was AN. Also, it was slightly smaller but did mount in the hole. I used parts from my stock to make it work. I can't tell you exactly what is needed. I think it's a 4AN, but not for certain.



Ran it for 30 minuets to test and be sure it didn't leak. Readings are where they should be.



Last thing to figure out is the darn fuel filter. With the pressure going to high in the system, I don't want to change it over like I had planned to. I don't know if the fuel filter side has that much, but my guess is there is a reason they used the hefty one they did.

Filter is part number 1752030-01 and the gasket is part number 1752036. TM shows the whole assembly as part number 1752029-01 and calls it a fluid filter, NSN 2910-01-312-1406.

 

[CallMeColt]

Updated my lat post with the missing picture.

Fiddled a little this morning with more stuff from my hoarding bin and was able to change out the external fuel connection with some stuff from an MEP 802A that I parted out so it is the same connection as the fuel hoses from the generators if I want to connect to an external source. Had to make the valve a little crooked to make it all work but doesn't effect anything.

 

[CallMeColt]