Low hot water pressure

[Matthew.yeoman3]

Hello all I am new to the forum as we just purchased a 2022 Grand Design Momentum 351M. I am having problems with the hot water pressure only when the water is hot and not all the time. I currently have my regulator set at 45psi just before going in the nautilus system. Before turning on the water heater I check that both cold and hot have good equal flow. After turning on the water heater later I can go try the hot water and it’s about 50% less pressure. 20min later I can try it again and it’s about 20% less than the cold. All this time the cold water stays at the same pressure never fluctuating. I am currently beyond confused and not getting much from my dealer since they are 8hrs away. Thoughts?

[DarnDave]

Matthew.yeoman3 Welcome aboard!! If this happens on multiple faucets, there must be some kind of obstruction in a line coming out of the water heater, which expands with heat. Or a valve on the Nautilus isn't fully open to the correct position. I've never had this happen. Fluctuating water pressure on both hot and cold, yes, when the park is on a well with pump cycling. I usually set my regulator for 60 to 70 psi at the hose bib. The inline hose filter and on board whole house filter both take a chunk out of that pressure.

Dave

[Country Campers]

Hello all I am new to the forum as we just purchased a 2022 Grand Design Momentum 351M. I am having problems with the hot water pressure only when the water is hot and not all the time. I currently have my regulator set at 45psi just before going in the nautilus system. Before turning on the water heater I check that both cold and hot have good equal flow. After turning on the water heater later I can go try the hot water and it’s about 50% less pressure. 20min later I can try it again and it’s about 20% less than the cold. All this time the cold water stays at the same pressure never fluctuating. I am currently beyond confused and not getting much from my dealer since they are 8hrs away. Thoughts?

Please let us know what water heater that you have, tankless, or tank. If it is the tankless there is a flow control valve on the right side of the heater, open the outside access panel. Caution though as you allow more flow the water temp will be less, less flow higher water temp. You may also have an obstruction as noted above but check flow to all fixtures.

Brian

[howson]

Hello all I am new to the forum as we just purchased a 2022 Grand Design Momentum 351M. I am having problems with the hot water pressure only when the water is hot and not all the time. I currently have my regulator set at 45psi just before going in the nautilus system. Before turning on the water heater I check that both cold and hot have good equal flow. After turning on the water heater later I can go try the hot water and it’s about 50% less pressure. 20min later I can try it again and it’s about 20% less than the cold. All this time the cold water stays at the same pressure never fluctuating. I am currently beyond confused and not getting much from my dealer since they are 8hrs away. Thoughts?

There was a Reflection 337 with a similar issue. Check out this thread as it will provide all the info you need to verify if the problem is the same on your Momentum: https://gdrvowners.com/forum/operati...t-no-hot-water

Also, check out the Welcome Letter to New Members here: https://gdrvowners.com/forum/main-fo...to-new-members

Howard

[Matthew.yeoman3]

@DarnDave I will give a try to the pressure regulator at the bib who doesn’t like more pressure.

Country Campers we have the 340011 : WATER HEATER SW12DEL 12 GALLON WATER HEATER W/ONE PC GAS VAL.

howson thank you for the link I will be trying this next week before we roll out again.

I have tried all the faucets and they do the same thing. I’m hoping that the check valve or something is a little gummed up at the rear of the tank. I will definitely let y’all know how it ends up.

[Country Campers]

The check valve may be the issue. Get a replacement brass one so when you take the plastic one off to check you can replace it with the brass and be done with the plastic, that has been known to have issues.

Brian

[Matthew.yeoman3]

Country Campers do you happen to know what threads that should be? 1/2” NPT is what I’m assuming.

[Country Campers]

Country Campers do you happen to know what threads that should be? 1/2” NPT is what I’m assuming.

Yes sir that is correct. Here is one similar to what I have, might be the same one, https://www.amazon.com/Valterra-P234...17733165&psc=1

Brian

[Matthew.yeoman3]

Country Campers well it seems to have made a difference. When I took the old check valve out there was nothing in it, so I’m not sure what the problem was.

Why is there a check valve there anyway? I’m assuming so when you turn your system to bypass the water heater you don’t get any bleed back.

[Country Campers]

Matthew.yeoman3

Yes the check valve is used to prevent back flow, mostly for winterizing so the tank does no fill with 12 gallons of antifreeze. Anther check you can do is the back of the Nautilus panel for any lines that may be bent too sharp causing a kink, check all lines anywhere you can see them but we have seen a few on the back of the panel. As the water gets hot the kink may close more.

Brian

[KSC_Travels]

Matthew.yeoman3

Yes the check valve is used to prevent back flow, mostly for winterizing so the tank does no fill with 12 gallons of antifreeze. Anther check you can do is the back of the Nautilus panel for any lines that may be bent too sharp causing a kink, check all lines anywhere you can see them but we have seen a few on the back of the panel. As the water gets hot the kink may close more.

Brian

Beyond the check valve, since this gets worse over time as the water heats up, I would also be suspicious of the P&T valve and/or the air "dome" or "gap" inside the hot water tank. Check to see if the P&T valve is dripping a lot when the tank heats up. This could indicate a faulty P&T valve. Or it could also mean that the tank does not have the right amount of air inside it. One easy check would be to drain the hot water tank (after first removing water source and pressure and opening the P&T valve - CAUTION WATER WILL BE HOT) and then closing and let it refill again. This should reset the amount of air in the tank.

[Country Campers]

Beyond the check valve, since this gets worse over time as the water heats up, I would also be suspicious of the P&T valve and/or the air "dome" or "gap" inside the hot water tank. Check to see if the P&T valve is dripping a lot when the tank heats up. This could indicate a faulty P&T valve. Or it could also mean that the tank does not have the right amount of air inside it. One easy check would be to drain the hot water tank (after first removing water source and pressure and opening the P&T valve - CAUTION WATER WILL BE HOT) and then closing and let it refill again. This should reset the amount of air in the tank.

Also make sure to turn off electric and gas so the heater does not come on when it is drained, yes I did this and ruined my electric heating element one time, lessoned learned the hard way.

Brian