Big Maxx Propane regulator

[Mmfh]

Hey there,

Big Maxx 75k Propane unit. Seems to me the control of the propane pressure is done inside the gas valve, is that right or does it need a regulator like the ones you see on the 20 lb tanks? It has a Honeywell VR 8205m.

I got this heater from a buddy, and he had a regulator at the tank bringing down the pressure before it got to the heater. Seems like that is double regulating and probably won't hurt but seems unnecessary.

Maybe its safer to run low pressure up to the heater, than to run high pressure and regulate it down at the heater. Can't find anything in the manual about using a regulator. Its says use a valve and a drip leg and that's it.

He also had a One way valve in the line before the propane reached the heater. Is there any reason to use a one way valve and a shut off valve??

I've installed this in my shop, and would like to clean up any unnecessary items in the supply line before I call this install done.

Regulator needed?
One way valve needed?
What do you think?

Thanks

Mm

[nehog]

AFAIK, it requires a regulator. TSC has them along with (long) hoses.

[Mmfh]

Seems funny that nowhere in the owners manual does it say to use a regulator. Also, the kits you buy to change from Propane to Natural gas say you need to adjust the pressure at the gas valve for the type of fuel you are using as part of the conversion.

Do you see any reason to use a one way valve in the line? Propane can go toward the heater but not the other way. Why would you need that?

[nehog]

Originally Posted by Mmfh

Seems funny that nowhere in the owners manual does it say to use a regulator. Also, the kits you buy to change from Propane to Natural gas say you need to adjust the pressure at the gas valve for the type of fuel you are using as part of the conversion.

Do you see any reason to use a one way valve in the line? Propane can go toward the heater but not the other way. Why would you need that?

1. I'm not a Big Maxx expert, so I could be wrong, but I don't know of any heater that doesn't use a regulator.

2. Not sure why they say a check valve is required. My heater (a Dayton) has a gas shut-off valve and a drip leg, but no check valve that is external to the heater's own valve.

[Mmfh]

Thanks Peter I appreciate your input

Mm

[58Yeoman]

I've got a Maxx, and the propane gas company put a new double acting reg on the tank that I bought (not from them). He said that eliminated having two regs; one at the tank to drop the pressure, and one at the building to drop it further for the heater.

When he installed this reg, he was doing it at the same time they were changing the regs on the house tank; they do it every so many years (I've only been here for four). The house has two regs.

I don't have a check valve in my feed line.

[Mmfh]

Originally Posted by 58Yeoman

I've got a Maxx, and the propane gas company put a new double acting reg on the tank that I bought (not from them). He said that eliminated having two regs; one at the tank to drop the pressure, and one at the building to drop it further for the heater.

When he installed this reg, he was doing it at the same time they were changing the regs on the house tank; they do it every so many years (I've only been here for four). The house has two regs.

I don't have a check valve in my feed line.

Thanks for that info, I'm going to leave the regulators alone and not use the one way valve.

Thank you!

Mm

[dave67fd]

Yes you need a reg. but you shouldn't need a 2-stage regulator for the BM . I't would depend on your line length and number of appliances etc... More precise line pressure and efficency for the appliances. Typically don't regulate at the heater (inside a building) unless you plan on piping the bonnet vent ouside. Your reg. should be mounted at the tank.

Your line pressure should be about 11-14" wc minimum. Manifold pressure should be checked at the heater but shouldn't need adjustment unless your in high altittude.

[Mmfh]

I haven't checked my pressures but with a regulator at the tank, and hooking it up to see how it works, nice blue flame on all the burners.

Seems to work great, I now have the ability to work anytime I want too. Didn't do much work at night before as it was just too cold and I wasn't able to warm it enough for my taste. Now about 15 minutes and I'm as warm as I want to be.

Thanks everyone for the tips!

Mm

[IONH]

I'm 99% sure the 75k heater manual mentions something about 10psi in it somewhere. I bought a 2 stage LP regulator from Home Depot for about $45 with a 3/8" outlet. Works fine so far (see signature for recent pictorial).

[Alchymist]

Could that "check valve" you refer to be an excess flow valve? Some places are requiring them for gas appliances now.

Originally Posted by IONH

I'm 99% sure the 75k heater manual mentions something about 10psi in it somewhere. I bought a 2 stage LP regulator from Home Depot for about $45 with a 3/8" outlet. Works fine so far (see signature for recent pictorial).

You sure that wasn't 10" WC instead of PSI?

[Mmfh]

Originally Posted by Alchymist

Could that "check valve" you refer to be an excess flow valve? Some places are requiring them for gas appliances now.

I hadn't thought about a valve for excess flow, that would make sense although I tried to use it at first as it had been used before, and I could not get anything to go through it.

Once I took the valve out of the line the propane flowed to the heater. I played around some blowing through the valve and as soon as I would blow just a little bit through the hose that valve would close.

Acted like a One way valve to me, or a very sensitive excess flow valve?

[IONH]

Originally Posted by Alchymist

You sure that wasn't 10" WC instead of PSI?

No, not sure at all.

[dave67fd]

I'm 99% sure the 75k heater manual mentions something about 10psi in it somewhere.

There's always that 1%

Line pressure should be 13" w.c. for LP,
gas pressure with unit firing at max rate is 10.4"w.c. for LP and
manifold Pressure should be set at 10" w.c. LP

If you have 10psi gas pressure, RUN and don't shut the light out when you leave.

Just a couple of general comments about your install.

1) Not sure of your description on mounting but looks like heater is only mounted at the center mounting holes. If you haven't already done it i would mount with the outer ones as well. The heater weighs in excess of 60lbs

2) You could mount the thermostat on a small piece of thick foam to isolate better if needed. Cut from a cheap foam work matt.

3) I'm pretty sure your vent doesn't meet code or manuf. specs unless you have cleaned it up since. The maximum horizontal vent length shouldn't exceede 5'. That includes the 1' minimum outside. 3' minimum length. Also all vent pipe fittings should be sealed with high temp sealer and the b-pipe exposed annual area should be filled. This eliminates any exhaust from entering the garage. I know this is temp install but this should be done. Still be easy to remove.

Gas line looks good.
Funny how Mr. Heater installed a terminal block outside for thermostat unless you did that.

[IONH]

Originally Posted by dave67fd

There's always that 1%

Line pressure should be 13" w.c. for LP,
gas pressure with unit firing at max rate is 10.4"w.c. for LP and
manifold Pressure should be set at 10" w.c. LP

If you have 10psi gas pressure, RUN and don't shut the light out when you leave.

Must have been W.C. that I remembered, you are correct.

Manual, page 12 at the top left. "minimumof 5.0" w.c. for natural gas or 10.4" w.c. for LP/propane gasshould bemaintained for proper unit operation."

[Martha39]

Seems funny that nowhere in the owners manual does it say to use a regulator.

[dave67fd]

Originally Posted by Martha39

Seems funny that nowhere in the owners manual does it say to use a regulator.

It doesn't tell you what size tank or where the tank should be mounted either.

However It does tell you to follow NFPA gas and local/state codes. The tank/regulator, gas line, vent etc.. is supposed to be installed by a licensed proffesional who will know better. The manual assumes that it will be installed by such as with any gas appliance.

I would rather pay a "licensed" pro to install my system so even in the rare chance my garage blows up or god forbid kills someone. I as well as my insurance carrier will know who to point the finger at and i get a new garage. Good luck convincing your agent to cover your cost because you did something incorrectly.