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Anyone Ever install a Williams Monterey Furnace before?

1661 Views 13 Replies 6 Participants Last post by  pragmath
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Has anyone installed a Williams "Monterey" Furnace - model 2509622? In the instructions (Figure 14) they show gas piping configurations - however I do not see how any of these arrangements are physically possible with the gas coming in from the stud wall.


In the instructions (Figure 5), the Alternate Gas stub location is 4" above the sill plate.


So, how does this fit in with Figure 14? I need for the shut off valve to be in an unconcealed space, and with the 3" sediment trap, there simply is not enough room underneath the furnace to fit it all! I've been looking online for a photograph of a properly installed wall furnace, and cannot find one.

In (Figure 24) they have a drawing of a Drip Leg (which differs from a sediment trap).
According to the UPC (which I am under), I need to install a sediment trap (like is shown in Figure 14) NOT a drip leg (As is shown in Figure 24).

I could possibly install the heater in the configuration shown in Figure 24... But it would still not be possible to use rigid pipe from the ground joint union to the gas valve because the female portion for the gas valve sticks out into the room a few inches. In other words, it is not a straight line from the hole in the stud to the hole in the gas valve. I think I'm allowed to use flexline, though - so that is why I could possibly do the install in Figure 24... but is it correctly installed if I do it that way?

Any help you can give me with this installation would be great!





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It is called getting a licensed plumber in that can do the gas piping for you legally, not some hacked together solution.
Hi Gregory -
Sorry, your reply was not helpful. My permit is "owner builder," and I looked up the rules on "owner builder." As an owner builder, you are legally allowed to work on your own gas piping. My final installation will not be a hacked together solution, but instead a permitted and inspected installation. I came to DIY Chatroom for some help doing that, and to make absolutely certain that I have followed all of the rules before I call the inspector to come out. I assume you do not have any constructive input - but if you do, I'm still open to it!
Thanks!
I've installed numerous Williams wall heaters and many times a drip leg wasn't required especially if the gas supply line rose vertically through the floor. Double check your local code to see what they require. The installation manual I believe uses national codes which may not be accurate or required by local codes.
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Thanks, kirwinjd.
We're under the UPC, and I did read in Chapter 12 that a "sediment trap" is required - they even have a picture of it that looks like the configurations in Figure 14. I did more research online, and determined that a "drip leg" is not the same as a "sediment trap." I need a "sediment trap." So, now the question is: how to I accomplish that when coming in from the stud wall? I've got 4 vertical inches to work with. Hmmm...
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I get a owner Builder allowance also when working on my home, but it still does not make me a licensed hvac specialist, or the ability to be a expert in gas piping.

The key is, if you do not know what you are doing, even though you have the instructions in front of you, you call in the experts. As for the location of the drip leg, depends on how the gas piping is run, and if the framing was not put up to take in consideration of that wall heater you are putting in, you will have to make some changes to make it work.

But still take it from someone who knows their limits, call in an expert to do the gas piping. More diyers messing with gas appliances have caused homes to blow up, than experts that do this stuff on a every day basis.
Those instructions you are reading would mean absolutely nothing where I am from...... must follow the B.149..
Hi Carmon - Well, I've read the UPC too. I see what I need to do according to the UPC - so perhaps I should just ignore the part in the instructions that says to set the feet of the furnace on the sill plate. I went over and looked at an installed one (same county), and they raised it up a few inches higher than my instructions say to. This would fix the issue of the sediment trap not fitting (interestingly, the installed one I looked at did not have a sediment trap or drip leg - but it was put in several years ago).
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For what it's worth, I've repaired countless Williams wall heaters and I've yet to see one that had a drip leg or sediment trap. I'm not suggesting that these were all installed properly or improperly. But because of the tight working space, it seems that the building inspectors in my area over look that requirement.
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Kirwin - Thanks for your helpful comment. That is good information to have. I think I'm going to just move the heater up a few inches to accomodate the sediment trap. The manual says a minimum ceiling clearance of 16", which is easily attainable. It frustrates me that the diagrams they show in the manual are physically impossible to assemble. I think that I have the best chance of pleasing my inspector if I add the sediment trap. Thanks again!
I'm in the same boat. Please throw a line if possible. Hard to believe/understand how Williams Co. deemed those instructions fit to print. Thanks, Jon
Kirwin - Thanks for your helpful comment. That is good information to have. I think I'm going to just move the heater up a few inches to accomodate the sediment trap. The manual says a minimum ceiling clearance of 16", which is easily attainable. It frustrates me that the diagrams they show in the manual are physically impossible to assemble. I think that I have the best chance of pleasing my inspector if I add the sediment trap. Thanks again!
you sure will because it is a requirement...remember neatness... inspectors love that..and yes just raise it up alittle higher that should be fine....ben sr
Here is what I learned...

I'm in the same boat. Please throw a line if possible. Hard to believe/understand how Williams Co. deemed those instructions fit to print. Thanks, Jon
Hi Jon - So, I did what I said I would do: I raised the furnace up about 5.5 inches from the subfloor (so 4" above the sill plate), if I remember correctly. As such, everything fit perfectly in a standard 8' wall with a double top plate; the distance to the chimney was fine. In the end, the instructions are poorly written, but I squeezed a nice little drip leg in there, and if the inspector had looked at it, I'm sure he would have said that was great... but he just came and signed everything off without looking around much. You'll notice that the furnace has these legs that are supposed to stand on the sill plate, so I just cut two 4" pieces of 2x4, and secured them to the studs to make very small platforms for those thin metal legs on the furnace. Then, to get the gas line in from the side, you have to drill through not one, but two 2x4s (the little one you added and the stud), but there is enough room for everything if you do it this way. All inspectors are different, I'm sure - so no guarantees that this will please your inspector - but I must say that doing more could possibly be better than doing less. This is just a theory, but when the inspectors first started coming around, they spent more time looking at my stuff. By the last several visits, they just checked things off. My suspicion is that they know what to look for at a glance - and don't need to get on their knees and look at the big details. One thing that might also help you: I had to do a pressure test on the line. So, it would have helped to NOT put the valve part on until after the inspection. I had to take it off to put on a cap so I could test at 10psi for 24 hours. The gauge was only $10 or $20, and I was able to pressurize the line with my bicycle pump.
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Thanks fulmar2 for the details. In my case I'm replacing an existing 50 year old two sided unit. Gas line pokes through the stud about 3" above the bottom plate. If I modify everything to raise the new one up it seems that from across the room the area without drywall underneath, will now be visible. If I were to patch in the drywall it seems I would then be limiting the service access to the "drop" leg, and therefore negating the whole purpose of this exercise. Chopping a 1/2" pipe cap width section out of the bottom plate (providing another 1 and a 1/2 inches) could seemingly avoid this whole problem but code may indicate otherwise.
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