gas WH question

[corvairbob]

ok we talked of a tankless WH and locations. however a few plumbers and the furnace installer are now telling me i should get a tank heater an put it in the laundry. the laundry is fresh air or makeup air setup for the dryer and they said that was plenty for both the dryer and the WH running. but the furnace guy is telling me he does not like the idea of running a vent thru the ceiling across the roof line to the back of the roof and the builder does not want the vent showing in the front of the roof. the furnace guy said to find out from the mfg if a power vented WH can be vented down into the crawl space and to the side of the house about where the dryer is going to be vented. i'm going to install a back draft on the dryer so that does not draw air back into the house as the laundry has bi fold doors so cold air can wind up in the house.

i have 24" from the side of the washer to the wall one way and 36" the other and he said that is plenty for an 18" WH but he does not know what brand makes 18" WH that have a powered draft. i email a o smith 3 times and have yet to get an answer. so does anyone here know of a WH that might do this job? thanks

 

[corvairbob]

possible WH vent to the left of the front door then porting away from the door 2-3' and to the right of the door the dryer vent and using one of those gravity vents to keep cold air from drafting back into the laundry and in the house. and to keep it a bit higher than the 12" for possible snow drifts? most likely i would need to run the WH up some for that same reason. so if i can do the WH would i need to put the vent exhaust further from the wall or would the heat be dissipated enough by the time it ran 20' from the WH to the end of the vent?

 

[Sponsor]

 

[John Gayewski]

Your vent needs to come out of the roof if your going to come out on that side of the house (in the picture) you can't vent a water heater within ten feet of a window. The exhaust gas is poison. You need to pipe it out the roof. Unless you want to change the windows to windows that don't open.

 

[corvairbob]

ok i forgot about that. thanks for that reminder, we sure do not need that issue. so it is back to the drawing board. this is kind of evolving thing. the furnace guy is looking at now putting the furnace back in the crawl space if he has the room for the plenum. and then using the closet they made for the furnace to put the WH in and vent thru the house roof on the back side. but if he can't do the furnace down in the CS then put the furnace in that closet and put the water heater in the garage and maybe it has to go in a closet insulated to help keep it warmer. and then venting that thru the garage roof. so i guess we will see. i'm just looking for options. i'm also looking at a tankless gas WH but now you got me thinking that may not work either as it will be direct venting out the back wall and again it will be withing 10' of windows. but i will measure that distance tomorrow to see. and if i was to vent a tank less out the back wall it will be 90% wast wind so again that may be a good distance but the wind may just blow the vent gas into the house when the windows are open.

so the last option i have would be locating an 18" gas WH and venting that thru the roof and that would be in the laundry. the issues that bugs me is even though that room is vented from the crawl space it may wind up going out thru a wall to the outside to keep the house warm air from going up the WH vent. as the doors to the laundry are byfold and about 1' off the floor. so we may be in a pickle either way. now i have an electric WH and i may have to just go with that and be happy. thanks.

 

[John Gayewski]

Get a Navien and vent it through the roof. Run 2" through a wall up into the attic then change to 3".

 

[corvairbob]

ok it looks like that navien uses pvc for the vent? so condensing. if that is so could i put that in the laundry room? they built that room for a tankless heater. and then run the vents into the attic, that will be easy and then out to the gable side of the house, either over the garage roof or out the other gable and termanate them there. i can do like they did for the furnace leave the exhaust straight and the inlet with a 90 deg down facing elbow. pvc will be way easier to install. so if i can go over the garage roof i can go out over the garage for the vents. see photo i could go about half way between those roofs? or just go to the other end that is flat. but the garage end is easier to work with


it seems no box store sell that navien in muskegon mi. ferguson does but i bet they will not sell to a homeowner only to the trades

at navien site i input 2 people and got the NPE-A2 model that looks easy enough to install but to source one. doing online search the one they suggested was the mpe-a2 series and that one can do 75' vents and 24' 1/2 gas line

also menards has the richman brand and the encore brand. i can get one of them and it should install the same as the navien does. the encore will do 60' vent run 3/4" gas input size so either should be fine.

so doing the condensing i can use pvc and then run the condensate to a drain in the CS


so condensing will be the best way and cheaper fr venting. the builder just does not want to go thru the roof to keep vents from road viewing and i bet he just does not want to mess with resealing the roof. going out the side walls should be easier and cheaper as well. i was asking to get a vent in the front on the garage for installing an antenna and he balks at that. so after he is gone i will have to do that later, if i need on as i now have that on the back garage.

 

[Fitter30]

Condensing wh the flue and combustion air have to be on the same side of the building can use a concentric vent termination kit only one hole for penetration.

 

[corvairbob]

ok guys as it turns out i can put either type of tankless in the crawlspace. the plumbers were out to set the hose bibs and turn the water on. and i was talking about someone saying the vents have to be 10' from doors and windows that will be open. they said here it is 3' to open doors and windows so they said i can do either type of heater as i have the distance per code and the plumbing is stubbed there and i have a drain for condensate. they recommend the condensate type as they are more efficient. they said that is the only type they install. so it may be back to the beginning. i'm going to shoot the inspector a photo of that area and see what he says. if he is good then i will get one soon and install that.

i'm not a fan of the water pressure and volume i'm getting from the hose bibs. they did 1/2" pex i may go and redo them to 3/4 pex at the main line that is now 3/4" pex, but that will be a next year project. have to get the water going the gas and power.

thanks

 

[John Gayewski]

I

ok guys as it turns out i can put either type of tankless in the crawlspace. the plumbers were out to set the hose bibs and turn the water on. and i was talking about someone saying the vents have to be 10' from doors and windows that will be open. they said here it is 3' to open doors and windows so they said i can do either type of heater as i have the distance per code and the plumbing is stubbed there and i have a drain for condensate. they recommend the condensate type as they are more efficient. they said that is the only type they install. so it may be back to the beginning. i'm going to shoot the inspector a photo of that area and see what he says. if he is good then i will get one soon and install that.

i'm not a fan of the water pressure and volume i'm getting from the hose bibs. they did 1/2" pex i may go and redo them to 3/4 pex at the main line that is now 3/4" pex, but that will be a next year project. have to get the water going the gas and power.

thanks






View attachment 105785View attachment 105786

I don't think it's that simple, but I use upc guidance for these things. Upc water heater section (chapter 5) is like 50 pages, ipc (Michigan) is like 3 pages.

Generally the water heater you get will have vent termination information with it. Use that and guidance from your local plumber.

I can tell you that the best way to do it is to terminate through a roof. If it's easier and more logical to go through the wall below a window jusake sure your looking at the information that comes with the heater you get and checking with the local inspector.

 

[corvairbob]

i would use that guideance but i hate to buy one and then find out it will not work. and like i said i have the water lines all stubbed out now for putting one on that back wall and i can get a condensate unit so i can run 2" pvc directly to the back rim joist 4" from the unit. i can move it over some to equal out the distance between the windows. the inspector said to go by the install instructions but i do not see those when i looking at them online at lowes and menards etc. they have specs but no installation instructions for placing the vent form a window. and i looked at the mfg website and i do not see instructions for installing them. at least for the richaman i think will work for me

Richmond® Encore® High-Efficiency 9.5 GPM 199,900 BTU Tankless Natural Gas Water Heater​

Model Number: RMTGH95DVLN-2

so maybe some one here has the install specs? this unit said it and run 60' for venting it is a powered vent and 1/2" gas line but i think the furnace guy will do 1" to this unit if i go in the crawl space as it will be about 30' from the meter and i have a line going to the back garage for a furnace out there that is 1/2" and ran good before i had to tear down the house.

 

[GReynolds929]

https://cdn.menardc.com/main/items/media/RHEEM001/Use_And_Care_Manual/AP22530-Rev-01-Manual-Tankless-Condensing.r1.pdf

Pg.34-49

 

[Fitter30]

i would use that guideance but i hate to buy one and then find out it will not work. and like i said i have the water lines all stubbed out now for putting one on that back wall and i can get a condensate unit so i can run 2" pvc directly to the back rim joist 4" from the unit. i can move it over some to equal out the distance between the windows. the inspector said to go by the install instructions but i do not see those when i looking at them online at lowes and menards etc. they have specs but no installation instructions for placing the vent form a window. and i looked at the mfg website and i do not see instructions for installing them. at least for the richaman i think will work for me

Richmond® Encore® High-Efficiency 9.5 GPM 199,900 BTU Tankless Natural Gas Water Heater​

Model Number: RMTGH95DVLN-2

so maybe some one here has the install specs? this unit said it and run 60' for venting it is a powered vent and 1/2" gas line but i think the furnace guy will do 1" to this unit if i go in the crawl space as it will be about 30' from the meter and i have a line going to the back garage for a furnace out there that is 1/2" and ran good before i had to tear down the house.

All the distances/ clearances for flues/ combustion air are not from the manufacturer but from different codes. When you seen a drawing of a house in a install manual the different code organizations are listed at the bottom of page. That why there all the same. Flue / combustion air size, length, material and ells have to followed 100%.