Home>Discussions>PLUMBING>Not sure what sort of water heater to go with
7 posts / 0 new
Last post
Phonedave
Not sure what sort of water heater to go with
Phonedave

I currently have an electric water heater that is nearing the end of its service life. I want to replace it with gas (there is gas and a flue located near the existing water heater - the WH is next to my gas boiler and there is a spare stub on the gas manifold) Here is my dilemma. The chimney is lined, with one thimble (for the boiler). The boiler enters the flue at 63" - too low for a standard water heater to tie in, and pushing the limit for a low boy (there would be about 6” of vertical before the 90 in order to keep a ¼” per foot slope). In addition, a low boy would fit the space, but it would totally block access to the water meter and shut off which is BEHIND the boiler in a corner. Right now I can reach around the current WH to get to the shut off, a low boy would be much wider (don't blame me, I didn't build the house). Now I could go with a power vent or condensing WH, but it would have to vent out through the garage, not from the laundry room where the WH is (the window and second story overhang means I can’t put the exhaust/intake out of the laundry room exterior wall). Or, I could go with an indirect water heater tank off of my boiler - but how will that be in the summer (my boiler is on the first floor of my split level house with no basement). Or, I could go with a tankless unit, making accessing the water meter in the future MUCH easier, but we still have the venting issue, and now I would have to determine if my gas service can handle the BTU demand of both a tankless and boiler firing at the same time. Of course if I punch a new hole in the chimney, insert a thimble, and add a tap to the liner, we could put in a standard height water heater - but adding that thimble is a job and a half.

I have no problem hiring someone to do the specific job - or heck, even doing it myself except for the indirect (I'm not plumbing and wiring in another zone myself) or punching a new thimble (my wife would kill me if I destroyed the chimney) - so any ideas? What sort of WH should I go with? This is a 4 BR, 2.5 bath house, with 3 girls plus my wife. We have a fairly high hot water demand. We need a high recovery system, and a pretty good tank size (if going with a tank unit)

HandyAndyInMtAiry
Re: Not sure what sort of water heater to go with
HandyAndyInMtAiry
Phonedave wrote:

I currently have an electric water heater that is nearing the end of its service life. I want to replace it with gas (there is gas and a flue located near the existing water heater - the WH is next to my gas boiler and there is a spare stub on the gas manifold) Here is my dilemma. The chimney is lined, with one thimble (for the boiler). The boiler enters the flue at 63" - too low for a standard water heater to tie in, and pushing the limit for a low boy (there would be about 6” of vertical before the 90 in order to keep a ¼” per foot slope). In addition, a low boy would fit the space, but it would totally block access to the water meter and shut off which is BEHIND the boiler in a corner. Right now I can reach around the current WH to get to the shut off, a low boy would be much wider (don't blame me, I didn't build the house). Now I could go with a power vent or condensing WH, but it would have to vent out through the garage, not from the laundry room where the WH is (the window and second story overhang means I can’t put the exhaust/intake out of the laundry room exterior wall). Or, I could go with an indirect water heater tank off of my boiler - but how will that be in the summer (my boiler is on the first floor of my split level house with no basement). Or, I could go with a tankless unit, making accessing the water meter in the future MUCH easier, but we still have the venting issue, and now I would have to determine if my gas service can handle the BTU demand of both a tankless and boiler firing at the same time. Of course if I punch a new hole in the chimney, insert a thimble, and add a tap to the liner, we could put in a standard height water heater - but adding that thimble is a job and a half.

I have no problem hiring someone to do the specific job - or heck, even doing it myself except for the indirect (I'm not plumbing and wiring in another zone myself) or punching a new thimble (my wife would kill me if I destroyed the chimney) - so any ideas? What sort of WH should I go with? This is a 4 BR, 2.5 bath house, with 3 girls plus my wife. We have a fairly high hot water demand. We need a high recovery system, and a pretty good tank size (if going with a tank unit)

Dave,
You have a boiler, why would you want to purchase a hot water heater. Use the boiler to heat water. I know there is a boiler fed water tank.

If you don't want to do that, I bought a 50 gallon direct vent hot water tank

For one, I would Never, Ever purchase anything for my home from any of the big box stores. Totally cheap junk.
You get exactly what you pay for. The local plumbing supply house in town is an AO Smith authorized dealer.

I just completed re-plumbing my entire house in 3/4" copper. I also put in a new natural gas water heater. I chose a one of the AO Smith water heaters. I like this one for many reasons. They also make a 75 gallon version, but with the fast recovery time of this one, almost double the price for only 25 gallons more, was not worth it. I have had this one for 7 months now. it has actually fired a total of 38.5 hours. We put this one to the test. 6 people taking a 1 hour shower in three different bathrooms, and no one ever went without hot water. All this and the dishwasher was running.

HTML Code:
http://www.supplyhouse.com/AO-Smith-GDHE-50-NG-50-Gallon-100000-BTU-Vertex-100-Power-Direct-Vent-Residential-Gas-Water-Heater-Nat-Gas
50 Gallon - 100,000 BTU Vertex 100 Power Direct Vent Residential Gas Water Heater

Always look outside the big box stores, you will always get higher quality.

Handy Andy in Mt Airy NC

Andrew

NashuaTech
Re: Not sure what sort of water heater to go with
NashuaTech

[QUOTE=Phonedave]Or, I could go with an indirect water heater tank off of my boiler - but how will that be in the summer (my boiler is on the first floor of my split level house with no basement).

Dave, You're gonna drive yourself nuts if you worry about working with gas flues, gas manifolds, power vents, punching holes in the chimney, or adding thimbles---there's no need for any of this!

Your post SCREAMS OUT for you to consider having an INDIRECT HOT WATER HEATER installed as a COMPANION to your boiler---sitting right next to it; if you're worried about residual heat from the tank in summer, be assured the tank is insulated; if there's no room next to the boiler, the IHWH can be easily located in any other location where there is room and that is convenient----their footprint is approx 2 to 2.5 feet and hold approx 40 gallons of domestic hot water (DHW is used for washing clothes, dishes, showers, shaving, etc.)--they are installed simply as an additional "zone" to your existing HW boiler heating/piping distribution arrangement & keep the internal tank 40 gal. of HW at approx 120-130 degrees until someone opens a HW faucet, or presses the "Wash" button on the dishwasher or clothes washer, or opens a "Hot" faucet when shaving, etc.---I think you will find that an indirect is the LEAST EXPENSIVE way to obtain domestic hot water (DHW) year after year, and these tanks last for DECADES, since there are no moving parts to wear out---the only caveat may be if you happen to have HARD WATER in your area, from a well or a local municipal supply---in which case I would recommend you simply purchase for your DHW needs an Indirect HWH with a STAINLESS STEEL TANK, or a GLASS-LINED or STONE-LINED internal tank that will prevent corrosive reaction to the hard water, and insure that your IHWH will last for decades without any problems---if you don't have a hard water problem, I would recommend going with a low-cost 40/41 gallon unit, such as the Amtrol BoilerMate WH-41Z for approx $900 plus installation---be sure to get AT LEAST 3 SEPARATE QUOTES from local heating equipment installers until you find the most reasonable deal---the install quotes could vary considerably amongst the installers.

Also when you talk to the installers, make sure they go over how many people are in the family, and calculate roughly how many gallons of HW are used on a daily or weekly basis---this will determine if you can get by with the usual 40-gallon tank, or if you'll need a slightly larger size tank----they have charts to calculate the usage of HW in gallons depending on family size & other factors-----many families can get by with a 40/41 gallon indirect----if you have any teenage girls, DOUBLE the HW gallon usage, because most teen girls like to take a lot of showers.

To view the various selection of indirect hot water heaters available, click onto the site below & enter into the search box "Indirect Hot water Heater"---the Boiler Mate by Amtrol is traditionally among the lowest cost/high quality units, but there are also good units by Triangle Tube Phase 3, HTP Superstor, Crown Megastor, Weil-Mclain Gld Plus, Lochinvar Squire, and TFI Everhot.

Also go to Google Search & enter Amtrol Boiler Mate and the other brand names above of indirect hot water heaters for more info and price offerings.

http://www.supplyhouse.com

Phonedave
Re: Not sure what sort of water heater to go with
Phonedave

I am leaning to an indirect fired unit, but the issue is not heat from the hot water tank. Heat from any tank - no matter how it is fired, is not the issue. It is heat from the boiler itself. Just to be clear, my boiler sits in conditioned space, in the center of the first floor of my house.

dodsworth
Re: Not sure what sort of water heater to go with
dodsworth

All boilers sold in the U.S. are required by law & code to have internal jacket insulation in order to prevent unwanted heat----unwanted sound is also often an issue.

Why not have several heating contractors over the house to get their take on the issue; some homeowners box in the boiler with fireproof & sound-proofing materials if the boiler is in the living quarters; also be aware that the ongoing combustion of the boiler flame requires an adequate supply of AIR in addition to the adequate supply of natural gas---this often requires an air duct from the outside to the boiler's combustion chamber.

Phonedave
Re: Not sure what sort of water heater to go with
Phonedave
dodsworth wrote:

All boilers sold in the U.S. are required by law & code to have internal jacket insulation in order to prevent unwanted heat----unwanted sound is also often an issue.

Why not have several heating contractors over the house to get their take on the issue; some homeowners box in the boiler with fireproof & sound-proofing materials if the boiler is in the living quarters; also be aware that the ongoing combustion of the boiler flame requires an adequate supply of AIR in addition to the adequate supply of natural gas---this often requires an air duct from the outside to the boiler's combustion chamber.

Make up air for the boiler is not an issue, neither is sound. The boiler is in a closet - sort of. There is a door to the hallway, but the other side if open to the laundry room. The point is, my boiler gets hot when it fires. Yes it is insulated, but it still gets hot. Insulation means nothing in terms of overall heat transfer. If I burn 100,000 BTU of gas for domestice hot water inside my house, it will eventually go into three places. Down the drain (where the hot water goes), up the flue, or into the heat load of my house. It's conservation of energy. Now, my boiler is fairly new, so while it is not super efficent, it is not a hog either, that means that not too much is going up the flue. Lets take a SWAG and say 10% - so for every 100,000 BTU I burn, 10,000 goes up the flue. So now the question is, of that remaining 90,000 BTU, how much goes towards heating water, and how much sits in my boiler to eventually raidiate out into my house, that in the summer, my AC unit then has to extract?

When the water heater calles for heat, the boiler is going ot fire. It will continue to fire either until the water heater is satisfied and signals a cut off, or the temperature in the boiler reaches it's set point. Either way, the boiler is still going to be hot when the water heater stops calling for heat and the circulator pump for the WH zone shuts off. That residual heat in the boiler will eventually raidiate into the house.

For the sake of argument, lets say I have a 50 gallon indirect fired tank, and I have city water at 65 degrees in the summer. How long does my boiler fire for in order to bring that initial 50 gallons of water up to holding temps (on average). Just how wfficewnt is the heat transfer between boiler and water heater.

Oh, and I talked to about 5 contractors - some say traditional fired WH, and they will tie it into the chimeny, others say go with power vent, other said what I really want is tankless, and then the last said that a inderect fired is the way to go. I have asked the question 5 times, and received 5 different answers.

-dave

bill
Re: Not sure what sort of water heater to go with
bill

You have to be carefull with indirect fire tank. This means running the boiler all year long. I question the economy of this action, even with a well insulated boiler, tank and pumps and piping, there is going to be thermal leakage. I would recommend a replacement with an electric hot water tank. better for the environment and economy. But then i live in Quebec with the cheapest hydro rates in north america.

Sponsored Stories

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.