Steepndeep
Well-known member
- Joined
- Apr 12, 2016
- Messages
- 139
Hi
Did not know how to properly phrase the headline but thought I would share my experience on how preheat works.
Last week I drove my son to training practice and it was -3C outside. Did not warm the car at all (using warmed seats only) so arrived at training with cold car AND cold ICE. Did some shopping and came back with minutes to spare on his training session and jumped into car and activated preheat via keyfob hack to have warm car on return. The following happened.
1 Very low level hum started, had to turn radion off to hear it, and no air came into cabin. Waited a minute but no change. Started looking for potential faults but could not detect any obvious, so continued waiting and freezing.
2 After 6 minutes suddenly the fan came on and ramped up to full speed during 30 seconds and then remained at full speed for 3,5 minutes blasting heated air. Then preheat stopped, as it should after 10 minutes.
3 Started preheat again and fan came on instantly.
Explanation is that as the electrical heater does not heat the air directly but warms part of the ICE cooling circuit it takes time to warm the water sufficiently to heat the cabin. I was just not aware of how long time it takes to heat the water, and this was at -3C outside.
So conclusion is that for preheat to have any effect at temperatures below freezing you must at least preheat for 20 minutes.
A proper implementation by Mitsu would have been to have cooling circuit temperature as part of the algoritm. In my case if I would have preprogrammed (not use keyfob hack) and choose the preheat to start at say 1800 the car would detect it needs 6 min to get cooling water temp up sufficiently and then start preheat at 1754.
PS Funny the Mitsu engineers did not think about this, as they have clearly thought about a whole set of other things like warning signals for everything which cannot be turned off
Did not know how to properly phrase the headline but thought I would share my experience on how preheat works.
Last week I drove my son to training practice and it was -3C outside. Did not warm the car at all (using warmed seats only) so arrived at training with cold car AND cold ICE. Did some shopping and came back with minutes to spare on his training session and jumped into car and activated preheat via keyfob hack to have warm car on return. The following happened.
1 Very low level hum started, had to turn radion off to hear it, and no air came into cabin. Waited a minute but no change. Started looking for potential faults but could not detect any obvious, so continued waiting and freezing.
2 After 6 minutes suddenly the fan came on and ramped up to full speed during 30 seconds and then remained at full speed for 3,5 minutes blasting heated air. Then preheat stopped, as it should after 10 minutes.
3 Started preheat again and fan came on instantly.
Explanation is that as the electrical heater does not heat the air directly but warms part of the ICE cooling circuit it takes time to warm the water sufficiently to heat the cabin. I was just not aware of how long time it takes to heat the water, and this was at -3C outside.
So conclusion is that for preheat to have any effect at temperatures below freezing you must at least preheat for 20 minutes.
A proper implementation by Mitsu would have been to have cooling circuit temperature as part of the algoritm. In my case if I would have preprogrammed (not use keyfob hack) and choose the preheat to start at say 1800 the car would detect it needs 6 min to get cooling water temp up sufficiently and then start preheat at 1754.
PS Funny the Mitsu engineers did not think about this, as they have clearly thought about a whole set of other things like warning signals for everything which cannot be turned off
