Second Water Heater

  My kitchen is a LONG way from my electric water heater, which is under
the floor beneath the downstairs bathroom. I'm thinking about adding a
second water heater under the floor under the kitchen sink. (A tankless
water heater is not being considered, and there is no inside cabinet
space to accommodate another water heater.)

1. Can a short body propane water heater be installed in the crawl
space? If so, does it have to be vented to the outside, or is venting
into the crawl space sufficient?

2. Is there any reason that I cannot put a valve going into the hot
water line at the kitchen sink that will allow me to switch between the
present electric hot water heater and the new propane one?

3. My house is plumbed with 3/4" copper, but the line going to the
kitchen is only 1/2". Shouldn't that line be upgraded to 3/4"?

4. What is the optimum water pressure for the house? My last plumber
reduced it because it was way too high. Now it's too low.

The reasons I want to use propane are that we have a large propane tank
for our gas logs. We don't use the minimum amount each month, so we can
get some of the heating energy for "free". Second, if the power goes
out, we'll still have hot water, and our power does go out way too often.

 
It's sufficient if you don't want to live long. Your floor is not
airtight and the crawlspace is likely not positively ventillated. The
CO will work its way up into your living space and poison you.


What would be the point? Why keep water hot if you're not going to use
it?


Most houses are only plumbed with 1/2"


Get the plumber back and make him increase the pressure.

 

All codes are local, you need to call your local plumbing inspector. If it's
allowed, you will almost certainly need to vent it properly.


No, but it sounds unnecessarily complex.


Not usually. Increasing the pipe size makes you waste more water and time
waiting for the hot water to arrive.


Between 50 and 60 psi is considered normal. Exceed 50 and you increase the wear
and tear on the valves in your house - especially the washer & dishwasher
solenoid valved.

 
How far is a LONG way?  Fifty feet? 100 ft?


space?
Yes

 >>>>If so, does it have to be vented to the outside, or is venting
into the crawl space sufficient?

Needs outside vent, it's a no-no to vent into the crawlspace.


water line at the kitchen sink that will allow me to switch between
the
present electric hot water heater and the new propane one?

Why bother?  Propane usage mentioned below?


kitchen is only 1/2". Shouldn't that line be upgraded to 3/4"?

NO!   A larger line will increase just increase the wait time.  My
kitchen faucet has 30 ft of hot water line feeding it (1/2" nominal
PEX) and the wait is ~10 secs.


reduced it because it was way too high. Now it's too low.

I installed a pressuring reducing valve to bring the city water
pressure ~75 psi down to less than 65 psi.   Plumbing systems are
suggested to have less than 65 psi to minimize water
hammer...personally I prefered the higher pressure.




for our gas logs. We don't use the minimum amount each month, so we
can
get some of the heating energy for "free". Second, if the power goes
out, we'll still have hot water, and our power does go out way too
often. <<<<<

If you want to optimize your propane usage, you'd need to "start &
stop" your propane heater use.   I guess you could feed the one water
heater with the other and turn one off depending on the propane
usage.    This might set up a situation for Legionaire's, something to
think about.

cheers
Bob

 
Sounds like an ideal place for a point-of-use or tankless water
heater.  I've used them several times now and they work great.