water heater check valve issue?

as the water pump cycles on and off while using the shower, you get a blast of cold water when the pump comes on. this started about 1 week ago. the pump has always cycled on and off as the pressure goes up and down so i am not thinking that is an issue. however i never had the problem of getting a blast of cold water every 5 seconds or so while showering. i'm wondering if a faulty check valve at the water heater might cause this? i do not have an accumulator so that isn't the issue.

You may have something blocking the hot water flow enough to slow it down some. An accumalator will fix the problem and give you a nice even flow of warm water.

I have replaced faulty check valve on the top of the water tank many times, on my unit and friends. The check causes a restriction that allows cold water to have greater pressure then the hot side. There is a spring in the check that creates this differential in pressure and is required to have the simple winterizing setup. I replace the check with a brass 1/4 turn valve and voila equal pressures on cold and hot.

When you winterize the unit you have to manualy shut the brass valve and then you place the 2 bypass valve in the bypass position.

That is the price you pay for conveniences, and sometime it will create an other maintenance problem.

i have the 3 valve winterizing system if that makes a difference.

Now that is different, you might have a hot water pressure loss in the piping somewhere. It has to be on the hot water side from the tank for sure.

i would assume that if there was a pressure leak somewhere the pump would cycle on and off even when there is no faucet open. this is not the case.

i have replaced the pump (i carry an extra one just 'in case'), installed a new check valve on the cold water inlet to the water heater, and installed an accumulator next to the pump. i no longer get surges and fluxuation in pressure, which is nice. now the water temp is steady as long as the water is flowing, but when you turn off the shower head to 'lather up' or what ever, the water dripping from the head turns cold until you turn the shower head back on at which point it gets instantly hot again. this is better than it was, at least i can take a shower now. but this is still not acceptable in my opinion. what else could it be?

The pressure loss on the water side is through the check valve if it is a spring type, a swing check might create a drag but not as much.

By pressure loss I meant a drop of pressure caused by restriction.

I to have placed an accumulator on the cold side in order to have a stedy flow at the shower head. Now the pump comes on and only stops when the pressure in the unit is ok and the flow stays steady, while the pump starts and stops during the shower.

So far it has not been a problem with our unit. But if it does the Check on the HW outlet will be replaced

It may be just me but I've never had a camper that didn't do just what your describing. I have added an accumalator on every unit, as a matter of fact I have moved the little one I have now thru the last 4 units. Its not as noticable when hooked to city water but when on the pump as we usually are, it does get cool when shut off a the shower head for a couple of minutes jon