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Hot Water

We live in a 65 year old house in New Jersey. During the winter months, the hot water does not seem to last as it should. This seems to correlate with the heater running. If you can hear the heater running, then you're almost guaranteed 2 minutes of hot water before it turns cold. Eventually, if you're in the shower for 10+ minutes, the hot water will return again, but minutes 2-9 are cool if not freezing. We have an oil furnace, installed 2005. I don't see a hot water tank anywhere near the furnace, so is it possible we don't have one? We've experienced this problem ever since the new furnace was installed in 2005. During summers, we have gloriously hot showers, but as soon as we start running the heater, the cold showers return. This also happens in the kitchen, so the problem is not isolated to the upstairs shower. I doubt it has to do with pipe insulation because as I said, the first few minutes of winter showers are warm, then fade to cold, and eventually turn warm again.

Has anyone else had this problem? What could be causing it?

Re: Hot Water

You'll need to tell us a little more about your heater. Look for a label, and a water storage tank of some sort, even if its inside a square burner box.

Re: Hot Water

I concur with HoustonRemodeler----many hot water showers and kitchen taps are not fed by a separate hot water heater next to the furnace/boiler---sometimes they're hidden inside the boiler housing or the furnace ducting and have limited hot water output of a gallon or so.

Could you tell us what kind of heating you have----do you have hot water radiators, or baseboard (a boiler); or do you have floor or wall registers where the hot air comes out for heat (a furnace)???

As HR noted, is there a LABEL somewhere on the front of the furnace/boiler that indicates the brand name, the amount of heating output, etc; please post any info you can copy down.

Have you had a local heating service technician over the house recently to see if the system could be adjusted to get a little more hot water out of the showers by making a simple adjustment???

Can you upload/post any photos to this site of the front of the boiler/furnace???

Re: Hot Water

Thank you both for the quick response.

I tried to upload images, but unfortunately there was an error in attaching them, so I hope the below information is enough.

Our heater is an OWT Boiler, Model No. OWT-4.
Series No. 1
I=B=R Input
LT Oil, gph....... 1.10 1.25

D.O.E. Hg. Cap.
(Water) Btu/h....a 129,000 145,000

Net I=B=R Rating
(Water) Btu/h....a 112,000 126,000

MAWP, Water PSI.....a 50

Min. Relief Valve Cap. LB/HR or MBH... 145

Maximum Water Temp F..............a 250

There is a tank strapped into the ceiling above the boiler, but the tank does not appear to be connected to anything and may be from an old system.

We have under the window radiators where hot air comes out.

We have not had a technician out to look at the system. I am not the homeowner, but I'm trying to gather information to convince the homeowner that it's not normal to have 2 minutes of hot water available.


Re: Hot Water

oh, you're renting?

Is there an old service tag giving a hint of the last time it was cleaned somewhere on this beast?

I'm gonna guess it hasn't been cleaned since there was a balanced federal budget. The tank and pipes can become quite clogged.

Re: Hot Water

I'm not renting...it's my parents house. Unfortunately, they are not the most responsible when it comes to household maintenance, so as a 20-something still living at home, I do my best to encourage them to take care of things sooner rather than later.

Case in point: Dad says the boiler hasn't been cleaned since it was installed in December of 2005 :o

Re: Hot Water

Okay, haleak2, lets see if we can get you a plan of action that will get you more hot water in the shower & not cost you an arm & leg in service fees.

1) you have a boiler there (not a furnace)---the boiler's main job is to heat the house & keep it warm; in addition, there is a small copper coil installed inside the boiler that holds aprox 1 1/2 gallons of domestic hot water (DHW) for showers, dishwashing, etc., called a "tankless coil"----this is usually in a black housing approx 7" that is round or rectangular; there is a thermostat box on the front of the boiler that usually is set to approx 140 degrees that is responsible for keeping the DHW constantly at this temperature so that you will have HW at the faucets & in case you take a shower.

2): Since the "tankless coil" holds a little more than a gallon of water that will get cold over time, the boiler comes on whenever the 15 gallons of water in the boiler cool off, because the DHW has to be kept hot & ready for use by the apt. occupant, or anyone else in the building that turns on the HW---this is clearly an awkward situation---if someone else upstairs decides to take a shower, or use the taps to wash dishes, etc., then YOU won't have any HW until the boiler comes on to heat up the 15 gal of boiler water to reheat the water in the domestic coil.

3): The first thing you should do is to get a new shower head that has a FLOW RESTRICTOR incorporated in its head---you should be able to unscrew the old one out & screw the new one in there---this in itself should extend the amount of time you can spend in the shower, since the HW will be coming out of the shower head at a slower rate, yet you should have enough HW to take the shower.

4): You will have to get the help of your dad, if he's the owner & responsible for paying for the heating tech service call, (or your mom) to call the heating co. so that they can clean the boiler & MAKE SOME ADJUSTMENTS ON THE DOMESTIC COIL CONTROLS so that the hw supply for the showers is extended---there's usually a charge of approx $25-$50 for a cleaning, plus any minor adjustments to the boiler.

5): Some things have to be done by the service technician to modify the controls on the domestic coil---this will entail slightly increasing the controls on the aquastat so that the water will be hotter (approx 160 degrees), AND AT THE SAME TIME, installing a tempering valve (mixing valve) on the line leading to the shower supply, as well as the sink & bathroom vanity supply, so that you are not burned by the hotter water---there may already be a TV on the DHW supply, in which case only an adjustment of the knob will be needed.

Post back if these remedial steps don't produce the desired results---there are other steps that people who have a boiler with a domestic coil eventually take to modify their heating system if they are unable to take showers, or the cost of the heating system becomes too high----most people have switched to natural gas (if it is available in their area), instead of oil, (OIL IS MUCH MORE EXPENSIVE); if the boiler is over 30 years old it's adviseable to replace it with a system that produces more DHW, burns natural gas, & is more efficient in burning fuel, & thus greatly reduces annual heating expenses.

The heating tech will check the water flow of the DHW coil tubing to make sure no minerals have partially clogged the inner surface of the coil so that there is good water flow & pressure coming out of the domestic coil----sometimes they have to run a scale remover solution thru the domestic coil to improve the water flow.

If none of the above remedies result in more DHW for showers, the heating tech can install either a "side-arm" DHW heater on the outside of the boiler, or else they can install a 30 gal or 40 gal indirect hot water heater---the latter will give you almost unlimited amounts of HW, but they cost over $1k; the "Side-Arm" is somewhat less expensive than the IHWH.

Re: Hot Water

Thank you, Pelton, for the very detailed response. We will consider a flow restrictor for the shower head. This sounds like a reasonable alteration, although I am concerned it will alter the water pressure as we are happy with the flow of water, but I suppose a hot shower is more important.

We are scheduling a technician to come service the boiler and will relay your tips to him.

Again, THANK YOU for your informed response!

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