I have a (WaterFurnace)  I noticed this morning the fault led was on, when I went to look at ther furnace control panel
I saw the the (Hi Pressure) Led was on. I tried to reset a couple of times but no difference. The manual says It's an air flow problem but the filter is new. It also says that it could be hi pressure in the cooling system but we don't use the air much and it's in heating mode. The fan runs fine,lots of air coming through the  registers. I'm thinking a faulty sensor ,any one have any ideas.

Thanks

How long since your last filter change and it the filter dirty? Is a reset meaning you pull the breakers?
CH

What model WF is it? If it has a Comfort Alert system installed it may help narrow down the problem.

Gastube,

Unfortunately, without being in front of the unit we are unable to determine what the issue might be. In cooling, the high pressure fault light could indicate a lack of water flow. We would suggest contacting the installing contractor to ensure that there is a sufficient flow rate to the unit. If your contractor is unable to find a resolution, please have them contact our technical support staff for further assistance.

WaterFurnace International, Inc.

Hi pressure is the result of poor or no air flow, or literally high refrigerant pressure.
I don't know how old the system is, but among the things I'd look for are a compressor running when fan isn't?
Does it trip low pressure if you run cooling (rules out air flow).
Is coil plugged even though filter is clean?
I have had a run on pressure switches the last year or two (regardless of brand) that would be my first suspect but hard for you to check on your own. Easiest to change the switch and see if trouble goes away.
Joe