Have a dyson hot cold fan keeps saying h2 and heat wont work any advice tried inplugging works for a few minutes then stops saying h2 again

TRY THE MANUFACTURER'S WEBSITE

quote from amazon site***Mine also showed H2. I had a suspicion that it was the remote causing it. Changed the remote battery (CR 2032), turned on the heater and let it circulate for 3 minutes, then I went and tested all remote buttons. It worked! No more H2 error code!
Amazon Customer · September 11, 2018

Hi Melissa.
see if this link helps you out.
https://www.google.com/search?q=How+do+you+fix+a+H2+on+dyson+hot%2Fcold+fan&rlz=1C1AVFC_enGB797GB798&oq=How+do+you+fix+a+H2+on+dyson+hot%2Fcold+fan&aqs=chrome..69i57.3127j0j9&sourceid=chrome&ie=UTF-8

what is the question?

I suspect that the microprocessor detected an overheat fault and is keeping it in E8 mode to prevent fire. The code needs to be cleared somehow. If it has some buttons on the front then try holding one whilst plugging it in. This may reset it. The reset will be something along those lines. Don't open it because if you can't fix it that way you need to take it back to the shop.

Check the flame sensor you still want to clean the flame sensor

Hi there, it's Jack at Dyson.

When you adjust the target temperature of your Dyson Hot fan heater (shown on the LED display on the base), you're setting the target temperature you would like the room heated to. The actual temperature of airflow produced by the fan heater will not vary.

If the heater won't run below 25 degrees, this is likely to be because the temperature of the room you're in is equal to or warmer than 25 degrees. The heater will only turn itself on if the temperature drops below 25 degrees, and once the room temperature reaches this target once again, the fan will turn itself back to monitoring mode.

I've attached our Getting started video below which shows how to adjust the temperature, using the remote or the controls on the base.

I hope this makes sense. It sounds as if your machine is working correctly, but if you'd like any further advice from our experts you can reach us at 0800 298 0298 (UK), 1-866-693-9766 (US), 1-877-397-6622 (CA) or 1800 239 766 (AU).

Fan bushings are shot. Replace blower motor

We had the same problem - the hot water would only be hot for 3 -5 minutes and shut off, then we had to turn the water off, wait a few minutes, and do it again. VERY FRUSTRATING.

Solution: The Rinnai serviceman showed me the heat-exchanger blower/fan: It was clogged with dust and moths.

Another clue: Our Rinnai was extremely noisy when the heat came on. After the fan was cleaned and replaced, it is nearly silent.

If you are reasonably mechanically inclined:
TURN THE BREAKER / POWER OFF to the unit.

The blower-fan is located in the lower central area of the unit (at least on our unit). If you draw imaginary north-south, east-west lines through the center of the unit, the fan is in the lower-left quadrant. There is a spring clamp securing the black rubber accordian-like tube to the fan. There are two screws that secure the fan to the unit. there are two plugs that connect to the fan, as well as a third air-flow sensor that should be removed. then you can look at the fan unit, as well as the grill on the underside of the heat-exchanger that should be cleaned.

My thought was to go out and get a simple bug-screen, and place it over the air-input outlet vent going outside, but the repair guy said that although it may sound good, if that screen ever gets clogged, or reduces airflow to the Rinnai, then the unit will work harder, or even shut off, giving the same problem.

This sounds like a problem with your fan motor. The dryer is getting too hot and the gas is shutting off until it cools down. That fan keeps the dryer cool by moving the heat to the clothes in the drum.
You can easily check this by feeling for air flow in front of the exhaust vent outside. No air movement = fan problem = heat shut off in 10 minutes. Good luck