New Furnace, Cold Showers.

kcammer

Please help. I have a brand new New Yorker boiler with NO separate hot water
heater.
My settings are as follows. Start temp 140 HL 180 HL dif 10 LL 160 LL diff 10.
Showers start out scalding hot and quickly go luke warm. If I wait long enough
it will get warm again but sometimes end up with cold water.
I have watched the boiler thermostat while my daughter is in the shower and this
is what happens. Anytime I check the boiler temp starts at 170ish. after
starting the shower within a minute or 2 the temp is down to 150. The boiler
does not fire until it reaches 140 and the temp continues to decrease down to
120 or so. I did try to set the low limit diff to 15 but I got an even colder
shower.

I have had this type of system for 20 years and never had a cold shower. The
only cold water intake value is what appears to be a normal shut off. I have
turned this down slightly to allow less water into the system at one time with
out much luck. My shower head is an eco head and was fine with the last boiler
so I don't feel that is the problem.
I do not have a mixing valve... would getting one help?????

The installer said the mixing valve wouldn't solve my problem. He recommended a
new shower head and scolded me for not getting the water heater that he
suggested.
As I said for 20 years and 3 homes I have never had a hot water heater and
always had endless hot water.

Update**** turn the cold water intake down a little more and got a 2 gpm shower head. Still not near perfect but better than is was.

Smith19

I gather that the boiler has a tankless coil built in?

Patchogue Phil_2

Don't know what kind of aquastat you have, but it is set to allow the boiler to get too low in temp for a tankless coil. Cold water cannot absorb enough heat through a tankless coil when the boiler is that low. If the boiler temp is 120° your cold water could be 50° or less. You won't get that cold water anywhere near high enough through a tankless coil, to take a comfortable shower.

Try 190° HI, 160° LO . With at least a 20° or 25° DIFF. Just my opinion, someone else here may gave better settings for a tankless coil boiler.

billtwocase

First thing, the installer should not be scolding you, he should be attempting to satisfy your needs with your investment. I am sure he got paid. I would hire first a reputable plumber to instal a mixing valve at the coil, have a qualified burner tech make sure the burner has the correct nozzle size, and have a combustion test performed. Then have your Lo limit set for 170, and your Hi limit at 190, differential of 10. Restricting the flow does help, but tankless coils are rated to heat "X" amount of GPM at 200 degrees. 120 degree boiler water will not transfer to make domestic hot water no way in hell.

EBEBRATT-Ed

The installer was way off base telling you you don't need a mixing valve. You need a mixing valve, and a flow restrictor, then you can adjust the aquatat to get what works

wogpa67

In this day and age when an installer comes in. Reads the rating plate on your previously oversized boiler, that was oversized by another 50k to cover the domestic. Then install the same thing without the flow restrictor that must be installed and no mixing valve!
I won't install a boiler with a tankless period.

bob eck

Where are you located? There are many good contractors that can help you out.

kcammer

thanks for all the great information. Turning the cold flow down that was going in did help with the hot water lasting during the shower. The water is still just way to hot to comfortably do dishes. I know from all your posts that something is not right. i do have a different contractor coming on Friday to check it out.

billtwocase

Nothing wrong with a tankless coil, just needs a mixing valve

icesailor

kcammer said:

thanks for all the great information. Turning the cold flow down that was going in did help with the hot water lasting during the shower. The water is still just way to hot to comfortably do dishes. I know from all your posts that something is not right. i do have a different contractor coming on Friday to check it out.

If you look in the I/O manual that came with the boiler, and it came with a indirect hot water coil, the manufacturer of the boiler requires that there be a proper flow regulated hot water tempering valve be installed in the original installation. It wasn't done. It needs to be done. Its a safety issue. If it was installed in Massachusetts, it was installed illegally without a plumbing permit. They are required to be there.

EBEBRATT-Ed

The REASON you need the mixing valve is that the boiler with a tankless can't hold a constant temperature so as the boiler cycles on and off on the aqustat your domestic water temp will change. Also, when the boiler is off the temperature in the tankless coil where the hot water is trapped (your domestic hot water) will rise up to the boiler water temp.

You really don't want 190 degree water coming out of your shower somebody will get hurt.

the mixing valve mixes some cold water into the hot water to maintain 120-130 degree water (when it needs to) (the mixing valve is adjustable). Tankless heaters are rated to provide say 3gpm @200 deg. boiler water. The flow restrictor should be the same size as the tankless heaters gpm rating (or preferably a little smaller) this prevents overdrawing the heater. The same thing you did by closing the valve part way.

Between aquastat adjustments and the mixing valve and flow restrictor someone that knows can set this up to be workable.

Tankless heaters are not the best you might consider an indirect tank when you can.

Patchogue Phil_2

If your shower can be temporarily scalding hot, you should consider getting an anti-scald shower mixing valve body.

icesailor

You need a thermostatic mixer on the tankless coil. If you have the boiler manufacturers I/O manual, it clearly states that you MUST install them with the correct flow control valve to prevent scalding. Which you are surely getting with out the valves.

It's in the manual. What breed of boiler do you have?

Here is the I/O manual for a Model of New Yorker boiler. Read page 14.

http://www.newyorkerboiler.com/pdf/104338-03 (AP-U) w .pdf