Blue Point, NY · Member since 2015 · 88 posts · 31 votes
Title says it all... this is in my personal residence but I’ve found BP to be a more credible source for answers than searching the web.
After 2 or 3 showers the water gets cool/lukewarm, not freezing and will stay that way, can usually get away with a shower in the morning and one at night without problems but if it’s the kids in the tub and a shower that pretty much uses it up.
Typical usage, nothing too long, any help? Also the water never gets really hot even though the unit is turned up.
Thanks in advance.
Westchester, NY · Member since 2018 · 115 posts · 52 votes
8y
What size is your waterheater? What is its configuration?
I had a similar issue in a 4-plex I bought last year. Root cause was a single tankless system that wasn't sized right to suply the house; maybe there are no tankless for that size ... The solution was to install a standared water heater (~40 gal) downstream from the tankless as a holding vessel. No issues now.
It degrades the hot water efficiency (read: more $$), but it is probably more efficient that having a 80 gal monster.
(1) Is the unit sized properly? Just Google "Water Heater Size Guide". If the size if appropriate, then
(2) Drain the unit completely. Sediment builds up in water heaters and should be drained each year to remove the sediment. Too much sediment could be problematic. If it is still not working, then:
(3) Check that the element(s) are not burned out. They are replaceable
(4) If all this is foregone, then it might be time for a new water heaters. Water heaters typically have about a 10 year lifespan.
Architect · Papillion, NE · Member since 2015 · 1k+ posts · 840 votes
8y
I bet you have a 40gal tank. This would happen if all the showers are taken back to back. You either need to add a second tank or replace it with a larger one. I believe gas takes longer to heat the water but more cost efficient but don't hold me it.
From google search:
The average American shower uses 17.2 gallons (65.1 liters) and lasts for 8.2 minutes at average flow rate of 2.1 gallons per minute (gpm) (7.9 lpm).
Rental Property Investor · Jersey City, NJ · Member since 2011 · 1k+ posts · 876 votes
8y
More info is needed about your equipment and what your tank temp is, and include what house heating you have. there's lots of answers like raising the temp and adding a mixing valve if you don't have one, but I need to know more.
Handyman · Pittsburgh, PA · Member since 2018 · 5k+ posts · 13k+ votes
8y
Dip tube on the water heater. Classic symptom. Look it up, pull the tube and check. If that's it, it will force you to reconsider BP as a credible source of answers.
Dip tube on the water heater. Classic symptom. Look it up, pull the tube and check. If that's it, it will force you to reconsider BP as a credible source of answers.
Good call, but in my experience with that you'd not get 2-3 showers. What a pain that was! The indirect tank was so full of tiny plastic shards I had to put a Y strainer on the output.
You have my sympathies, Johann. Musta been tons of fun.
Wasn't hard to solve once I knew what the problem was, just minor plumbing. It was figuring out where the sandgrain sized pieces of eroding tube plastic clogging the showerheads and faucet strainers were coming from that was the real challenge! I got help in a plumbing forum.
@Johann Jells. Where did the plastic sharDS come from? Did you get a deal in Chinese Pex at Dollar General?
The dip tube was literally disintegrating. When I tried to extract it, all I got was a ring of plastic from the top as the rest fell inside! Apparently Triangle Tube got a bad batch of dips.
Blue Point, NY · Member since 2015 · 88 posts · 31 votes
8y
@Shaun Palmer appreciate all the resPonses, didn’t expect this much feedback but thanks to everyone...
So it is a 50 gallon electric water tank but is being used as an indirect holding tank off the boiler with a circulator... I’m pretty clueless on this side but that’s my understanding so let me know if it doesn’t make sense or you need other info.
Appreciate all the help...
@Shaun Palmer appreciate all the resPonses, didn’t expect this much feedback but thanks to everyone...
So it is a 50 gallon electric water tank but is being used as an indirect holding tank off the boiler with a circulator... I’m pretty clueless on this side but that’s my understanding so let me know if it doesn’t make sense or you need other info.
Appreciate all the help...
Is your tank electric and your boiler gas? Weird. And is the thermostat on the tank controlling the circulator just like if it was a regular indirect?
So assuming the dip tube is OK, and nothing is broken or wrong in the system, the next step is to know what that thermostat is set for. If it's set for domestic hot waster temp of 115, we have room to play and improve your system. If you set your tank to 140-150, you have a whole lot more heat in there. Now you add a thermostatic mixing valve on the hot water out of the tank to reduce it's temp to 115. This not only effectively increases your hot water supply, but makes it safer. It's become known that Legionella bacteria can grow in the 115 range, but not in the >140. Many pro's now only do this type of installation with the higher tank temps.
I'd like to know more about the boiler. this setup can be really inefficient in the summer depending on the model and how it's implemented. My boiler that heats my indirect was cycling all day in summer when no one was using hot water just to maintain the temp. I bought a programmable thermostat on which I could widen the gap between hi and lo temps, so is would not cycle all day and the cold start boiler could go cold. If your boiler isn't cold start you're doing even worse, as it stays fully hot 24/7/365.
Rental Property Investor · Cedar Park, TX · Member since 2014 · 414 posts · 272 votes
8y
You say the water "never gets really hot." It could be as simple as a bad control valve, which shuts off the heater prematurely. I have the opposite problem -- the water staying hot with the valve on the vacation setting. The manufacturer sent me a new valve under the warranty, and I'll install it today.
Blue Point, NY · Member since 2015 · 88 posts · 31 votes
7y
@Johann Jells Thabks again, it turns out it was the heat exchanger between the boiler and the storage tank. Replaced that and it is working fine.
The repair guys did mention getting rid of the tank bc it’s older and going to a tankless instead of replacing the exchanger. I did the exchanger to be done with it for now but may do the tankless in the future.