Water heater dilemma: New valve or new unit?
December 12, 2015 12:58 PM   Subscribe

Our Northern VA household of three adults recently lost its hot water, due to a failure somewhere in the works of our natural-gas, tank-type water heater. Having wrestled this appliance a few years back to replace (what I thought to be) a faulty thermocouple, I was initially pretty confident, but that confidence has begun to ebb as the battle enters day four.

I'm starting to think a new heater might be worth considering, but we are shockingly cash-poor, and I'd dearly love to pull this scenario out of the fire. Or would that be, to put it back into the fire? Moving on...

We believe the current heater (a Whirlpool model FG1H4040T3NOV) was installed just before we bought the house in 2004, making somewhere around eleven or twelve years old. Performance has generally been very good — even the "bad" thermocouple turned out to be fine once I got a meter on it, and I suspect a good cleaning would have solved the issue without replacing the part.

The problem today is the same as four years ago, which is that the pilot won't stay lit. This heater has a sealed compartment, so manual lighting isn't an option; good airflow and thermocouple voltage over 12mV are what keeps the FVIR valve open to supply gas to the pilot and burner. So I've dusted below the unit and around the burner and arrestor, and I've cleaned the thermocouple, which is now producing at least 15mV after forty-five seconds with the pilot burning.

Still, as soon as I release the pilot "reset" button on the gas valve, the pilot immediately dies. According to this troubleshooting guide, that means I need to replace the gas valve. To do so, I'd need to either spend $200 for an OEM replacement, or $60 for an "almost" replacement, with a strong chance of needing an adaptor — and possibly a wiring hack — to fit with our heater. Oh, bother.

So... Anyone know what the installation cost for a tankless gas heater (like this one) might run me? I think I may be out of patience, and willing to throw money we don't have to spare at solving this problem.

Any advice would be very much appreciated... I really need a shower...
posted by atavistech to Home & Garden (11 answers total) 1 user marked this as a favorite
Best answer: In the short term, a replacement tank-type heater would be the cheapest option if you can't fix the old one. You could likely replace it yourself if you have an appropriate flame source, some solder, and miscellaneous copper piping parts (the inlet and outlet holes are never in the same place between models, and flex-hose connections are rare on the water side), leaving your total cost at $400 or less.

You would, of course, need to ensure your water and gas shutoffs work before embarking on the project. A flood or unstoppable gas leak would definitely not improve the situation.
posted by wierdo at 1:15 PM on December 12, 2015

I'm definitely not an expert, but I went through much the same steps you described. After much mucking with the thermocouple and cleaning, I finally realized that I was getting low gas flow from the main line. My gas meter regulator was old and had snow in it. I called to the gas company they replaced the gas meter on a Sunday within 90 minutes for free. Low and behold the water heater worked again! Do you have any other gas appliances to verify your gas is working correctly?
posted by benk at 1:16 PM on December 12, 2015 [1 favorite]

We have a tankless water heater in this house, which was installed when we moved in. It wasn't something we were actively looking for when buying the home, but I'd never go back to a tank heater now that we have it.

Regarding cost, thankfully the woman who we bought the house from documented everything, so we know that the tankless Takagi heater + installation was about $2400. Our realtor indicated this was one of her favorite water heater brands, so is probably a touch on the expensive side.
posted by Verdandi at 1:56 PM on December 12, 2015

$2400 sounds ballpark. We had to run a new gas line, and had a new electric circuit wired.

Also, if you go tankless, be sure to get one big enough for your flow rate at the temperature differential you need. In the northeast US, the water supply in winter is often 55F or lower, so to pull 120F you need a 65F rise, and the nominal rating for heaters is typically 55F rise. And 120F isn't all that hot for hot water.
posted by mr vino at 2:00 PM on December 12, 2015

i once worked on a gas water heater, and it wouldn't stay lit after i'd finished fixing it. yay. turned out that it had additional thermcouples to detect hot air where it shouldn't be if it was vented correctly, and i had some problems with airflow. so i was (1) quite impressed at the design and (2) surprised at how i'd managed to break it without knowing. you might check if you have a similar problem and also double check how competent you feel (i know, i know, i normally fix things myself too).
posted by andrewcooke at 2:04 PM on December 12, 2015

I have a Navien tankless heater (both water & baseboard heat), which is a bit pricier than what you're looking at. But yes, you should expect multiple K to install one. If cash is an issue, you're probably better off getting another tank heater, if it comes to that.
posted by thomas j wise at 2:35 PM on December 12, 2015

If you need to replace your water heater: In addition to lower cost, a tank type water heater works without power, so you will at least have hot water during a power failure.
posted by H21 at 4:32 PM on December 12, 2015

Best answer: It looks like your current water heater is rated as a 9-year model. I'm usually all for repairing rather than replacing, but learned an expensive lesson when our over-aged water heater ruptured when we were away from home. The expense was easily 10 times the cost of a new water heater.

I really wanted to replace it with a tankless heater, and had a plumber estimate the cost. Found out it would have required a larger gas supply line, and a larger exhaust flue through the roof, so it just didn't make economic sense in our case.
posted by Snerd at 5:52 PM on December 12, 2015

Response by poster: This is all very helpful... and thought-provoking. Hmmm...

What I'm hearing has me leaning toward replacement with another tank model. Not as exciting as a tankless of course, but the idea of having to install a larger gas line and/or exhaust flue is a sobering prospect to one's pocketbook.

On the other hand, the current heater was purchased by the last owner for use by rental tenants, and I'm sure wasn't vetted for quality with much rigor. I plan to do my homework before plunking down any cash — mercifully, my fellow inhabitants don't appear to mind a few more days without "Hollywood showers".

Thank you, fellow MeFites... I knew I could count on your sage advice. :)

P.S. On a related subject, Fenriss and I are planning to draft the outgoing tank into service as a reservoir for the drip-irrigation system we're aiming to build in the spring... that should be a fun project... :D
posted by atavistech at 6:57 PM on December 12, 2015 [1 favorite]

It seems like you've got your answers already, but just to give you a bit more data:

We're in the District, and shortly after we bought our house in 2013 the heat pump died and through complications1 we also ended up installing a new tankless heater (they recommended a Rinnai, and it has been awesome). That added $3500 to the cost of our new furnace, but I would, in fact, recommend2 it if you can swing it.

Do you have a HELOC? Do you want one? We are currently refinancing because we found out we've got WAY more equity than we thought and it's getting us out from under the MIP on our FHA loan, and our mortgage guy has basically said to us that we should be getting a HELOC immediately after the refi closes3. That could solve your cashflow problem and get you the heater you (may) want.

  1. I wanted a gas furnace instead of a heat pump. They could install the gas furnace, but it needed to go in rotated 90° relative to how the heat pump air handler had been installed. Also to get the furnace into the closet they'd have to remove the water heater first, install the furnace, then put the water heater back. The old water heater dated to a renovation in 2009 and probably would have been fine, but meh. We wanted a tankless eventually anyway, and this way the work just got done. Well, except for the holes in the ceiling in the basement from where they had to run a new gas line, which we still haven't repaired…
  2. It hasn't actually lowered our summer gas bill at all. It was $15/mo with the tank; it's $15/mo with the tankless. What it has done is make lengths of showers inconsequential, and it also made it possible for us to host seven guests for Christmas in 2013 and never run out of hot water. But if you just want it 'cause it will lower your gas bill, I can't say that it will.
  3. He even made his mom get one. It has a zero balance. He said, "It's free!"

posted by fedward at 8:31 PM on December 12, 2015

I had a tankless installed in a previous house and we loved it. There was one caveat, which was that because of the layout of that house there were some long pipe runs, so it was necessary to install a recirculating pump to avoid long waits for hot water. (The recirc pump was on a timer, so it only ran during times of use, and I couldn't see any measurable cost other than installation.) I don't remember the precise price, but it was around $2000 including extending a gas line and installing the flue, and after the federal and utility rebates that were offered at the time.

In our case the utility bills dropped going from an old electrical heater to the new gas tankless, along with the benefit of endless hot water, but the exact payback time is going to depend on your utility costs and your usage. I have read that people often save less than they think they will because they end up using more hot water, and there is a possibility a tankless may not pencil out on economic terms at all.
posted by Dip Flash at 5:59 AM on December 13, 2015

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