Vintage Honeywell Gas Valve Replacement/Retrofit

ottov1

I have a gas furnace outfitted in the 1920s with a Honeywell gas valve, size 3/4, pressure 8 oz, Type VS887A27X2 G-LP. It employs a 300mV thermopile.

Can a replacement or a retrofit be had for the valve? Thanks.

SuperTech

Honeywell makes a universal replacement standard pilot gas valve that uses a thermocouple for sensing the pilot flame. They also make the Y8610U electronic ignition retrofit kit, this is morw expensive but it would eliminate the standing pilot and save a little gas. 

The boiler was installed a hundred years ago and is still in use? Please post pictures of the entire boiler!

ottov1

Thanks. It's not a boiler, but rather a converted coal furnace - gravity heat. House built in 1890. Furnace works great - house stays toasty warm. I've never had trouble with the valve - I replaced the thermopile some years back. I'm looking for replacement valve to store with the furnace in case the valve ever fails. Is there any preventive maintenance that can be done to keep the valve in good working order?

tim smith

That looks like an old Holland gravity furnace.

JUGHNE

Is this a thermopile self generating system? It has no 24 volt power supply?

mattmia2

Replacing that valve with a modern valve isn't just a swap in/swap out. There will have to be some retrofit to connect the pilot to the modern combination valve instead of the separate gas cock and the pressure and combustion will have to be set up. Either you will have to find a millivolt combination valve or add a transformer and swap the thermopile for a thermocouple and change the t-stat to a 24v model. It isn't a DIY project, you will need a good tech that understands how conversion burners work.

On the other hand sometimes valves stick open and that can be a safety issue.

ottov1

Thank you for your responses above.

This is a self generating thermopile system - no 24 volt supply. The valve has worked well as long as I've owned the home since 1984. I replaced the thermopile some years back.

I understand that retrofitting would be required if I cannot find an actual replacement. My goal here is to have the new valve on hand in case my vintage valve fails - I would solicit a furnace tech to perform the retrofit as required, but want to be sure I have the valve already on hand in case our heat failed. I have a 24V supply installed and ready, but am not using it at present. I have a modern electronic Stat that is configured to call for heat - this works well - it will also work for a modernized gas control.

The vintage valve is actually an OEM component of a "Janitrol Gas Conversion Burner" manufactured by the Surface Combustion Corporation. See photos below.

mattmia2

See the thing is that the type of system where it doesn't shut off the pilot if it goes out ceased to be approved sometime in the 60's or so, so just replacing the valve without retrofitting it to a total shut off system is a little questionable.

EBEBRATT-Ed

I agree with @mattmia2

That system although it may work well is sadly outdated. You can get a valve Honeywell #vs802A0154 or similar at supply house.com.

But why would you want to?

You would be much better off putting the $350 the valve will cost you into your budget for a new furnace. Your old one is probably 50% evvicient. A new furnace will save you 30-50% of your fuel bill

And your safety will be enhanced

Tim McElwain

It would help if I could see the pilot? A modern Honeywell VS820 Power Pile gas valve would replace the valve you have. I suspect the system you have is 750 millivolt system. Seeing a picture of the pilot and pilot generator would help to confirm that.

ottov1

The furnace is equipped with a 300mV gas valve. The current thermopile is working well and generates ~450mV when heated by the pilot with no call for heat. Using the newer valve will require the thermopile to be replaced with a 750mV version.

Tim McElwain

The only pilot generators made today are 750 millivolt generators. A picture of the pilot will confirm that what you have is probably a 750 millivolt generator. If you lift the cover off the gas valve and take a picture it would help.

ottov1

I'm an electrical engineer...

mattmia2

Tim worked for the gas company for like 50 years...

Tim McElwain

They used to make generators of 250 millivolts and 500 millivolts. They have not been produced for many years. You can replace them with a 750 millivolt generator.

retiredguy

One thing to remember when working with a thermopile or generators as we used to call them, is that due to the very low voltage produced, all controls , wiring connections, control contacts, and even the wiring that transmits that voltage must be in pristine condition. For example, that mercury bulb control that is above the door, may need to be replaced due to the mercury becoming dirty or oxidized causing it to have a higher than normal resistance to electrical flow. Years ago, when these were more common, a lot of the service calls were from loose wire connections dirty or worn out control contacts or someone installing a control that was not designated for use with a thermopile system. Most of the mechanical controls that had contacts, were "gold flashed" to help reduce the resistance to electrical flow. As an electrical engineer you should be aware of this. When I got into the heating business in the late 1960's these "octopus" furnaces were common place as were thermopile systems and they lasted for years and required no outside electrical power. As far as cost to operate, as @EDEBRATT-ED stated, there could be significant cost savings with a new unit but it will not last as long as this "BEAST" will. I like the cold air return just to the left side of the burner, just behind the 4x4 post. My 2 cents

ottov1

Thanks for all your input above. At this point, I'm not intending to replace the furnace as it works very well and keeps our home very comfortable even when -20F outside. I will be purchasing a newer gas valve and a 700mV thermopile to go with it, and will perform the upgrade during summer months - the $400 or so investment looks worthwhile to me, and I will still have a furnace that runs when power is out. The gravity heat system works very well in our 1890 home.

mattmia2

You will need a tech that can set up the combustion and draft with the new valve and regulator combo, it isn't just swap it and leave it. It would be a good idea to measure the rate it is currently set up to fire at before you do the retrofit.

ottov1

There are also two regulator (pancake) valves that I believe will need to be removed (one for valve, one for pilot) as these are integrated in the replacement valve, no?

mattmia2

Yes. that is all integrated in to the new combination valve. That is the part you need a good tech that knows how to do combustion analysis to set up.

mattmia2

Different valves open at different rates, if the old valve was slow opening and you replace it with a fast opening valve you may get delayed ignition and it may light with a small explosion.

ottov1

The existing valve opens very quickly - immediately with call for heat

Tim McElwain

My experience with this system and I have replaced many of them with an upgrade to a VS820 Powerpile valve is they work very well. I know they are old but old is not always bad. I looked up some of my combustion tests done on these systems in the past (yes I have records of all the jobs I have ever tested) the combustion tests ranged from 65% to 72% combustion efficiency. The history on these old systems is the folks who lived in the homes loved them and never found themselves cold.