Mounting tankless water heater to a vinyl sided building

[MarkE]

As discussed in this thread, we are going to put in a propane tankless hot water heater.

Our house has vinyl siding and the heater we are getting is an outdoor unit.

What is the best way to attach this tankless hot water heater to the outside wall of our vinyl sided house? Do I need to cut out some of the siding and mount to the sheathing? Or just add some kind of spacers (PT pine) on top of the siding? Or maybe sink a 4x4 post into the ground and mount the heater to that?

What would you do?

[Guy in Paradise]

I am not an expert, I just know what I have seen. You might want to explain what type of unit you have a little more.

I have lived overseas many years where tankless water heaters have been the standard for a long time. The houses are generally concrete or block and the heater is mounted right on the wall. The heaters generally run on kerosene and that tank is often on a stand so that the fuel gravity feeds to the burner.

In the USA, there seems to many various models, and the manufacturer generally provides guidance on how to mount to various walls, or even ground mount on a concrete pad and stand. Think I would call your local area construction codes office and ask. They should be able to provide some input. Cutting into the vinyl would reduce the potential heat contact, but will increase the chance of weather intrusion, and ultimately some real problems. Maybe bolting an exterior plate onto the wall and then mounting the heater on that might be the best, then there are only four, or so, bolt holes into the siding. Think I would still call the codes folks. Maybe even contact your house insurance coverage company and ask them, I am sure they would be interested to look it up for you. I would bet that the propane tank(s) have to be a certain distance away from the heater, and depending on size, from the house as well.

It is good that you are thinking about this instead of jumping right in and installing it in potential violation of any guidance that may invalidate any future problems. Good luck.

[Guy in Paradise]

Just read your other thread on the decisions and thoughts on an electric tankless heater. Lots of good information there. Glad you have focused on propane. In the end, it should be most painless installation. Sorry you have to go through the process of returning those electric units. Again, good luck with the project. Maybe you can write a book afterwards and recoup some of the expense. Getting all of the information in one source would be beneficial to many homeowners. I want a copy.

[merrill77]

If it were me, I wouldn't mount it through the vinyl siding. Vinyl siding is easy to break and hard to fix. I'd find or create something else to mount it to.

[Joe Scharle]

Mine's mounted directly to brick, but I'm sure they provide a standoff mounting plate.

[dave "dhi"]

Cut out siding and flash ur OSB board with a water proof membrane or galvanized flashing be then run a J-channel around ur box! Do NOT attach directly to vinyl! not level and now water can penetrate behind vinyl and you'll never know it. Whats bad about vinyl, can't see water damage behind it!

[FredP]

what dave said and in addition vinyl sideing moves a LOT! if you attach to it and restrict this movement it will pop right off the house! DAMHIKT....

[MarkE]

I have tried to find more information on exactly how to mount this heater and I am coming up empty. I have never worked with vinyl siding before, so this is all new to me.

If anyone can point me to a good resource on how to get this done the right way, I can probably do it myself. So far I have found nothing.

Maybe I would be better off just having someone else get this thing mounted. Is there anyone here that wants the job? Send me a PM... Please.

[gfernandez]

This may be an obvious question, but have you tried calling the manufacturer and seeing what they recommend?

[MarkE]

I have contacted the manufacturer. They say that the heater can be mounted with zero clearance on the back side. I asked specifically about mounting to vinyl siding. They will only say that is has to be mounted 'securely'. They do/will not give any additional instruction specific to different types of siding. They suggested that I contact a professional installer.

[ScottM]

Not sure of what the weight is you are talking about but I have had good luck attaching things to vinyl using clear silicone. Make sure it is the 100% silicone.

[MarkE]

I thought the heater weighed around 40-45 lbs. It actually weighs around 80 lbs.

It was delivered yesterday. Unfortunately, A natural gas unit arrived instead of a propane unit. I have to call the company today to get that sorted out.

I have had conversations with FredP and he is going to do the mounting.

[dave "dhi"]

Find stud of house, cut out siding and lag to stud! Refer to my previous posts! Have installed numerous things to vinyl homes !!! Self-employed contractor. Dave

[MarkE]

Finally got this thing up and running.

FredP came by and got it mounted to the building. After talking with the propane service guy and the plumber I ended up moving it about 12" higher on the wall. After watching Fred, I had enough confidence to do it myself.

Had to run a new wire for the electric. Put in an on/off switch and added a duplex outlet. The outlet can be used for a sump pump to flush the heater with vinegar once a year. Also ran wire for the remote thermostat to the garage. Mounted that just outside the door to the house.

The propane guy came by a couple of weeks ago, but he did not have the 3/4" pipe and risers needed. He got the parts and did the install on Monday. The plumber(s) got the water hooked up on Wednesday. Now we just have to experiment with the temperature to find the best setting. I had it set to 110 degrees, which seemed a little high for a shower, so I set it back to 108. LOML thought that 108 was not warm enough for washing hands/dishes etc, so it is back to 110. We'll have to see how that works.

[Joe Scharle]

FWIW, I leave my WHs set at 120 deg.