Where is anti-scald valve located?

[tired of cold showers]

Hi Lazy Pup,

From your post of 01/25/2005 : 20:41:53 you stated:
"Almost all of the anti-scald valves currently in use have a single control knob and an internal thermostatic action to maintain the hot water at a preset point, but prior to the introduction of the thermostic valves they made a manually adjusted "tempering" valve that constantly mixes a preset amount of cold water in the same manner as a tub or kitchen faucett mixer. The downside of the manual tempering valves is a wide variation in hot water temps from summer to winter as the cold water supply temperatures change."

Where might one find this valve? We built our house new in 1998. We have never been able to take a nice hot shower, but of late, the showers are barley lukewarm and to take a bath, we need to heat part of the water in the electric tea kettle. We had the plumber that built the house out once, but he only hemmed and hawed around and didn't really seem interested in helping us. We would really like to have comfortable baths and showers again. We have replaced all the inside components of the shower.

Any suggestions/direction would be greatly appreciated

[LazyPup]

As you pointed out in your post, prior to the common acceptance of the automatic thermostatic anti-scald valves manually adjusted tempering valves were in widespread use, and they are still readily available and commonly used.

The code requires that in instances where the water heater is also used for space heating you are required to install a master mixing valve to temper the domestic hot water to not more than 140degF. (International Residential code 2802.2)

The physical location of a WHOLE HOUSE TEMPERING VALVE or a WHOLE HOUSE THERMOSTATIC MIXING VALVE must be down stream of the point where the space heating line attaches to the water heater and should be before the first branch serving a hot water faucett.

It may be installed at any convenient location, but it must be open and readily accessible for service or adjustment.

I have attached an illustration of what you are looking for.

I would begin at the water heater hot water discharge port and examine the lines downstream from that point.

Some people erroneously install them only at the tub/shower so you may also want to look for a service access to the tub/shower mixer and see if the valve is located in there.

When these regulations first came out some people made there own tempering valves by placing a globe valve with a checkvalve between the hot and cold water lines, so look for any cross connections between hot and cold.

[tired of cold showers]

Thanks for your quick response. All we see is two flexible hoses going from the water heater into the drywall. If there is a whole house tempering valve, it must be somewhere on the other side of the wall (all though the other side of the wall is inthe breakfast nook). We checked every place we could near the bathrooms upstairs, but could not find any service accesses to showers, tubs or sinks. Seems the only faucet that has decent hot water is the tap in the kitchen. Even the garage faucet runs on the cool side. Short of punching holes in probable spots, we're pretty much at a loss. We have the layout diagrams for just about everything, HVAC, electrical, etc., but no plumbing diagrrams.

Thanks again for your help.

[LazyPup]

Thermostatic anti-scald valves or tempering valves are only required if the water heater is also used as a source for radiant heating or space heaters, or in instances where there is a commercial dishwasher that requires 180degF water supply. It is very likely that you do not have a termpering valve.

Try using an accurate thermometer to measure the temperature at the kitchen sink, bathroom sink and bathtub spout.

Next check the water temperature at the water heater. As soon as the tank thermostat turns the burner off the tank should be at its maximum temperature. Open the drain valve and measure the temperature of the water in the tank.

You may turn the tank thermostat up a bit if necessary. Just make sure the water at the tub does not exceed 125degF.

If you do turn the tank temperature up in winter, you should monitor it as the outdoor temps rise to make sure the tub water is no more than 125deg. By actually measuring the water temp you should be able to find a summer and winter setting for the tank and just make a point to change it seasonally.