Is the temperature coming out of the mixing valve close to the setting of the mixing valve? Temperature may not be exact but should be close.
Is the temperature at the faucet close to the same temperature as coming out of the mixing valve?
Is the temperature entering the mixing valve from the heat exchanger at least 20f higher than the setting on the mixing valve.
Check the flow at the faucet, does it exceed the maximum flow rated for the combi as follows?
PHNTMC-135…… 3.0gpm
PHNTMC-150…….3.7 gpm
PHNTMC-180..…..4.4 gpm
When the problem exists is the hot water being drawn at another faucet, dishwasher or clothes washer?
The flow must exceed the flow requirements with the second demand. Restrict to one demand at a time or install a flow restrictor on the cold inlet to the combi kit.
Is the high limit set to 180f in the “DHW” menu?
From that screen scroll left 2 screens. If the “Diff Above” is not set to 10f set to 10f press the Check mark to save. Did problem resolve?
Install a flow restrictor to meet the GPM flow sprec for the boiler size.
Clean or replace the plate heat exchanger
Look for cold water bleed over from mixing valves at washing machine, single lever faucets etc.
Set DHW high limit to 180f.
How to enter password
- Follow the steps below.
- Press the “Adjust” button twice
- Press “Login”
- Press the “Zeros” on the screen
- Type 86
- Press the return key on the right 8
- Press “Save”
- Press “Adjust”
- You will now see 6 rectangles on the screen. The lower right box will be “More”, pressing that will take you to the next page of menus. Pressing the “X” in the upper right hand corner will take you backwards.
- Any screen you make changes to may have a Checkmark √. That would mean save the change. If you leave the screen and have made a change and did not press the checkmark √ it was not saved. Not all screens will have a checkmark √.
