shower temperature fluctuations in old building - Plumbing Forum

bronc0 · 11-05-2010, 02:43 AM

I live on the 6th floor of a pre-war apartment building in Queens NY. Since moving in, I've noticed that the water temperature in my shower fluctuates wildly, from uncomfortably hot to uncomfortably cold. When I brought this to the attention of my landlord, he said that it was caused by other tenants flushing their (tankless) toilets, which caused an evacuation of the cold water in the pipes, causing the water in the shower to become momentarily hot. This would only account for the times when the shower becomes too hot, not when it becomes too cold. Also, the duration of these fluctuations is sometimes much longer than a few seconds. At times, I would estimate the temperature lasting for at least 30 seconds. My question is, is there anything that can be done inside my shower to help with this problem? I've read online about 'thermostatic control valves,' but I don't know if such a device would work for me.

**SlowDrip** · 11-15-2010, 01:33 AM

hi broncO,

Temperature fluctuations in old buildings are common since you have multiple sources drawing from the same pipes. If someone turns on cold water for a drink, there is less cold water supplied to your shower, if they want hot water for a bath then suddenly you lose some access to hot water. You probably won;t notice someone running a faucet for 5 seconds to rinse a glass, but a big draw like a toilet flushing or someone filling a tub will be noticeable

A thermostatic control valve, as you mentioned, will help with this. Explained simply, a thermostatic valve keeps an eye on the water pressure coming in to you shower from both hot and cold pipes. If pressure in one pipe suddenly drops it attempts to drop limit pressure from the other pipe by the same percentage, meaning that you will lose some water pressure but not experience a drastic temperature change.

In some cases you can find shower heads with a built in thermostatic control but the more common and permanent fix is to replace your current shower with a thermostatic unit.

Hope that helps!