(Almost) No Hot Water Out of Shower/Tub Faucet

[mcurrie84]

I am a new homeowner and am learning the ropes. We have a tankless coil water heater on our oil furnace. The hot water pressure in the entire house leaves a lot to be desired and has gotten worse as of late. I suspect the coils need to be cleaned and I'll get to that as soon as I can.

However, the main issue currently is the downstairs shower/tub. The only way to get reliable hot water is to turn the heat on in the house and have the furnace run for ~30 minutes. The sink in the same bathroom gives nearly instant hot water, as do the other sinks and the upstairs shower.

The shower/tub uses a Symmons Temptrol valve. Today, I replaced the Temptrol spindle (https://www.lowes.com/pd/Symmons-Chrome-Brass-Valve-Repair-Kit/1225865) and cap assembly (https://www.lowes.com/pd/Symmons-Ch...qTouNq1Zznsh1nwU6vhoCNxEQAvD_BwE&gclsrc=aw.ds). No change.

The cold water runs with full pressure, no issue. But the hot water is only about 85F and there is a slight pulse in both the pressure and temperature. Is there anything else that an amateur DIYer can check?

 

[Geofd]

There are 2 different stems that symmons makes, one is fore a tankless coil in a boiler
The other is for a hot water tank, if that's the only fixture that's giving you trouble that its the wrong stem you can get one at any plumbing supply house or call symmons
They are located in Braintree mass just off rt 128 it's call a 3 hole stem for a tankless coil in a boiler

 

[mcurrie84]

There are 2 different stems that symmons makes, one is fore a tankless coil in a boiler
The other is for a hot water tank, if that's the only fixture that's giving you trouble that its the wrong stem you can get one at any plumbing supply house or call symmons
They are located in Braintree mass just off rt 128 it's call a 3 hole stem for a tankless coil in a boiler

I'm looking into this now and I do see they have 2 part numbers: TA-10-RP (Temptrol Spindle in Retail Packaging - Symmons) which is what I bought and TA-10-3HL (Spindle, Limited Flow - Symmons) which does specifically say Limited Flow. I assume that the 3HL stands for 3 Hole, which is what you mentioned.

I'll call Symmons tomorrow as I've heard they have great customer service. Thanks for pointing me in the right direction!

 

[Geofd]

Ta-10 hl is what you want the three hole has less holes for the cold to mix thru, you will see the difference,,symmons is all we use here at northeastern University they are very well made yes customer service is great roo

 

[mcurrie84]

I was really hopeful that the TA-10-3HL 3-hole spindle would be the solution. Unfortunately, I just got one, installed it, and it is exactly the same as it has been. I then tried all 3 spindles: the original, the new TA-10-RP I picked up from Lowe's, and the TA-10-3HL I received today and the pressure and temperature were exactly the same.
The temperature coming out of the bathtub faucet was only 85-90 while the sink the same room ran 110+.

I know that my hot water pressure is low throughout the house which is an issue I have to deal with sooner rather than later, but I cannot figure out why this particular faucet is the only one that runs so cool.

 

[Twowaxhack]

I was really hopeful that the TA-10-3HL 3-hole spindle would be the solution. Unfortunately, I just got one, installed it, and it is exactly the same as it has been. I then tried all 3 spindles: the original, the new TA-10-RP I picked up from Lowe's, and the TA-10-3HL I received today and the pressure and temperature were exactly the same.
The temperature coming out of the bathtub faucet was only 85-90 while the sink the same room ran 110+.

I know that my hot water pressure is low throughout the house which is an issue I have to deal with sooner rather than later, but I cannot figure out why this particular faucet is the only one that runs so cool.

Your tub/shower valve is suppling more cold water than hot water ratio compared to other faucets it sounds like.

For kicks try this. Turn off the cold valve to your hot water source.
Bleed the residual pressure off the hot side and the water should stop flowing. If the water never stops flowing that means you have cross connection between hot and cold water or your stop valve at the water heater isn’t holding.

Do this test at the kitchen sink faucet.

 

[Twowaxhack]

I’ve heard of this problem a lot with Symmons valves. I’d probably just replace the valve. Maybe it’s your piping, maybe it’s not.

 

[wpns]

Do you have integral stops, and are they both fully on?

Have you checked the ‘maximum hot’ setting screw?

 

[Geofd]

That spindle will only work if your tankless is working properly, if your getting lower temps everywhere your coil maybe gumming up or your mixing valve (at the boiler) parts may need to be cleaned or replaced, another thing you can check with your symmons valve is, there's a small flathead set screw that when backed out allows the handle to turn further to the hot it should be flush or just past with the valve body, clean the tankless and check the functionality
of your boiler mixing valve before you do anything drastic I would put any other valve in, I've change those spindles out many times and it always cures the shower water issue symmons will tell you the same thing clean your tankless and make sure your boiler mixing valve is working properly