You don't mention your flow or filter condition. If the fan is running and the compresser is not, (no heat), you have a flow issue most likely related to a dirty filter. Is the operating pressure higher than normal?

the pressure is fine. it is a brand new pool so i don't think it is a dirty filter unless it is construction debris. i'm just wondering if the pb could have hooked some thing up wrong or if a setting is wrong. how fast should the temperature be rising during the day when the air temp is in the 60s or 70s? i mean, should it be taking several days to see any rise? or should we see a difference in a few hours? sorry for the lowercase, i am holding a baby and only have one hand to type.

"the pressure is fine. it is a brand new pool so i don't think it is a dirty filter unless it is construction debris."

Based on what? Is this a plaster pool? Was the filter cleaned after start up? Do you know that starting pressure vs the pressure now? A new pool can have a dirty filter after 24 hours of running on new plaster...

You could not answer your question on temperature rise without knowing how large the unit is. 60's - 70's is pretty cool for a heat pump. Do you have a 500, 700, 900, 1200, 1200 R H/C???

You could be configured for cooling too. Have you checked that?

If you have doubts about installation, you should have that checked first before you go crazy trying to figure out what's wrong.

Thanks for your thoughts. Yes, it is a plaster pool. I don't know about the beginning pressure, but yesterday the pool guy gave us a "lesson" and showed the filter pressure valve. He didn't open the filter, but showed us what to do. I don't know if it was cleaned after the plaster went on or not. He seemed to think the pressure was fine when he showed it to us, but who knows? I know we didn't have it set to cool, so that is not the problem. I will call the pool guys on Monday. They are a 2 hour drive away, so I don't know when they will get back out to check on it. The last time they came it was the coldest day in months. They had to rewire the remote, and said they were not sure the heater had been working prior to that. With the day being cold, we didn't expect to see much rise in temperature at that time. So I don't know if it has ever worked. It is a 5hp, 50 amp, 108,000 btu heater. It's just really frustrating that we busted our butts to get the pool done so we could swim this fall, and so far it feels like we have no heat.

We have a 20x40x30 L shaped pool.
We have a heat siphon heatpump 5HP.

When it is cold (50's / low 60's) outside we gain no heat.

Put your hand over a return and you should feel a slight temp difference when the heater is on. You should get a 1-3 degree rise at the return when heater is on.

We live near Boston and kept our pool at 90 until 8 days ago.

During the real pool season you will be happy.
You'll save a ton over propane or gas, but the propane or gas will heat much faster and later into fall.

UPDATE: The pool guy came today, and we have a bad compressor on a brand new heat pump. So they will be replacing it Wednesday. Thanks for your comments. Hopefully we will still sneak in some warm days to swim.