Speakman Shower Head draining a Viessmann 120 Gal. Indirect

Alan (California Radiant) Forbes

The title says it all. We installed a Viessmann Vitola Biferral boiler sitting on top of a stainless steel indirect 20 years ago. Owners have been happy until recently when a 15 minute shower starts to cool down. Have just ordered a replacement manhole gasket so that I can inspect the tank, but we have good water and I'd be surprised to find much accumulation.

The Speakman shower head is the large one with the flow restrictor removed and has worked fine for long showers until now.

Does anyone have any insight or experience on this?

EBEBRATT-Ed

Is there a dip tube in the tank that could have fallen off?

mattmia2

is there a tempering valve on the dhw that maybe is now stuck in one position?

JUGHNE

I have an old 120 gallon indirect that the dip tube failed.
I replaced it with ACR soft 3/4 OD with a flared end to prevent it from falling into the tank on the cold inlet.

Larry Weingarten

Ummm, Find a new showerhead? https://www.housebeautiful.com/shopping/g33584763/top-showerheads/?utm_source=bing&utm_medium=cpc&utm_campaign=arb_bg_hbl_d_bm_g33584763&msclkid=8176b8ed44601aea3451d8924fbcae70

Yours, Larry

Alan (California Radiant) Forbes

I'll check that dip tube when I open it up. It's at the opposite end of the tank from the manhole.

Larry Weingarten

Hi, Has the number of gallons used before it starts to cool down been figured out?

Yours, Larry

Alan (California Radiant) Forbes

Hi, Has the number of gallons used before it starts to cool down been figured out?

The shower head output is ~4gpm. I'd say 3/4 of that is undiluted DHW, so 3 gpm x 15 minutes = 45 gallons; 38% of tank capacity.

hot_rod

water pressure increase? Causing more gpm to flow.

Zman

You could clock the water meter to see if the flow rate changed, then clock the gas meter to verify BTU output.

Paul Pollets

I wasnt't aware that the Vitocell 300 stainless tanks had a dip tube.

ChrisJ

Alan (California Radiant) Forbes said:

The title says it all. We installed a Viessmann Vitola Biferral boiler sitting on top of a stainless steel indirect 20 years ago. Owners have been happy until recently when a 15 minute shower starts to cool down. Have just ordered a replacement manhole gasket so that I can inspect the tank, but we have good water and I'd be surprised to find much accumulation.

The Speakman shower head is the large one with the flow restrictor removed and has worked fine for long showers until now.

Does anyone have any insight or experience on this?

Is there a way to verify if this change happened all of a sudden or if it was over a long time and it's just at the point where they've had enough?

Is this in a bath tub? If so is the diverter sealing good?

Any chance it's actually a mixing valve issue (stuck in one position) and the water leaving the tank is actually still hot?

JUGHNE

I see from the picture that it would not have the conventical dip tube.
But it worked for 20 years.

Maybe control not firing for DHW early enough?
Low boiler side water flow?
Low fire on boiler?

clammy

I would think no matter what the water condition that after 20 years there will be some despots . I recently serviced a buderus tank that was installed over 20 years ago and noticed that the when firing had a very low delta and the boiler was short cycling on the limits a clear sign of a dirty heat exchanger ,upon opening I found about 1/4 to 1/3 of the bottom of the tank loaded w lime and calcium it can out to about 2 5 gallons buckets of junk the bottom 2 turns of the heat exchange where buried . Used a container and then a wet vac to remove brushed down the interior walls and the coils and flushed the tank put it back in service and now it’s like day one also replaced the anode and gasket and installed a long needed mixing valve . I be installed a few buderus vertical tanks and found there recovery not as good as a standard buderus but there’s a lot less strata faction in those hortizontal and it does play into the tanks out put capacity . I usually take a look at the delta t on tanks when the boiler starts if it’s low and I’m sure the pump is operating properly and was sized correctly then I know the tank is dirty . Great thing is at last it can be cleaned unlike most which are throw aways .i ve tried de liming indirects on my own tank and I would not do it for a customer even if the tank was set up w isolation and flush valves because it’s a long flush to get any de liming agents smell or taste out of the tank even after Numerous flushing and draining of the tank for myself no big issue but for a paying customer it’s not worth the expense and unless you can see the heating coil and ensure it s not fouled .. If you have hard water Have a water softener installed and you’re using an indirect it doesn’t have a manhole which most don’t you’re part of our throw away Society and just replace the tank . Even w tanks w manholes it’s still a hard sale in doing yearly or bi yearly inspection and maintance most are in the mind set of out ta sight out ta mind or the world famous break and react maintaince which seems to be something that never goes out of fashion .. I find that if when you install a complete heating system w a indirect that on the initial firing parameter should be recorded so in the future it takes a lot of guess work out of determining when a tank is fouled . Even if there not 5 gallons of crap on the bottom of the tank you can be ensured that there build up on the heat exchanger at a mim all the junk on the bottom of the tank is just what has come loose and has fallen off the heat exchanger and is sitting on the bottom of the tank . If she is clean I would look to pressure drop on the portable side I ve run across that time to time usually a blockage on the water inlet especially w do electric nipples and unions . Peace and good luck clammy

Alan (California Radiant) Forbes

I find that if when you install a complete heating system w a indirect that on the initial firing parameter should be recorded so in the future it takes a lot of guess work out of determining when a tank is fouled

I like that, clammy!

The boiler is in an ADU (Accessory Dwelling Unit) close to the main house and includes a small bedroom and bathroom. When I open the hot water tap (a high flow valve on a very deep bathtub; 60-70 gallon capacity and I can fill it completely with hot, undiluted water), within a matter of 3-4 minutes, the boiler kicks on for DHW production and stays on until setpoint (152F) is reached. Yes, that's a low setpoint for DHW production and I'll increase that when I go back. But the long run-time tells me that the pump is working and there's a steady heat transfer.

@Paul Pollets My mistake. It's the polar opposite of a dip tube, referring to the curved tube that extracts water from the top (hottest) layer of water. It could have broken off, pulling out mixed water.

@ChrisJ From what the owner says, it was suddenly noticed. It's a stand-alone shower, no diverter. And there's no tempering valve on the outlet.

mattmia2

is dhw priority working correctly?

ChrisJ

Does the shower have a mixing valve built in?

Alan (California Radiant) Forbes

@mattmia2 Yes
@ChrisJ It's a single lever, thermostatic shower valve and was tested in the fully hot position. When the water temperature started dropping, the same temperature drop was confirmed at the basin faucet.

ChrisJ

Alan (California Radiant) Forbes said:

@mattmia2 Yes @ChrisJ It's a single lever, thermostatic shower valve and was tested in the fully hot position. When the water temperature started dropping, the same temperature drop was confirmed at the basin faucet.

You're not making this easy...

mattmia2

120 gal? that's a lot of hot water.

Perhaps they have not cut their hair in over a year now and are now talking much longer showers?

Clamp a thermometer on the outlet of the indirect and conform that the temp is actually dropping significantly to rule out other plumbing system issues.

Alan (California Radiant) Forbes

@ChrisJ:

@mattmia2 Great idea! I used to have a Fluke meter that read temperature, but left it on a job.............somewhere. Any suggestions?

mattmia2

I just have an inexpensive extech thermometer and a fieldpiece clamp on thermocouple but I just use it for my own stuff. I bought it to be able to make reasonably accurate superheat and subcooling measurements.

You can always take a video of a few instruments/controls with your phone to skip through and see what is happening.

Big Ed_4

I would check the flow rate of the new shower head . Use a five gallon bucket and stop watch . Run for 30 seconds and double it . A 5 gal per minute flow rate would use 75 gallons in fifteen min . Since it is a horizontal tank you will loose 20% capacity or 96 gallons .....

Alan (California Radiant) Forbes

The end of the story is that we opened up the 120-gallon indirect this morning and didn't find anything wrong with it. There were some black flakes floating around, but no sediment and it looked brand new.
At this point, I think the shower head somehow changed and flow increased. The Speakman head has an adjusting lever and the owner may have changed that to more flow. We changed the head to one that has a max of 3.5 gpm.

mattmia2

I think the quarantine hair is also worth investigating. i haven't cut my hair in over a year and a shower now takes about twice as long as it did before.