farrel

I have Wren 44 with Autostart. from about a week ago, it starts to get flame out, even the EGT shows only 480 C but not so smooth start like before. I experience thie after I replace the propane tank coz the last was empty. I readjust the propane valve as the propane start to depleted (note, I have no on-board propane can), and now, after I get the new propane can, I don't know how to reset the valve to initial setting.
Now I set it for 1-1/4 turn and I have on-board propane tank. When I start it (with off-board propane can), still have flame out, but when I start it with on-board propane can, it is always time out, coz the gas can is empty. The setting is the minimum set I adjust. Less than (Tried to adjust just a very little opening until I can heas a "hiss" sound) or more than that, the motor won't start or experience hot start.
Is my gas valve setting was correct??or there is something happen with my motor??

Wren Turbines USA

My Feedback: (39)

First: Make sure you are not introducing liquid propane into the motor....what type of propane are you using ??

Do be sure your onboard start battery is healthy, as a weak battery will result in lower than acceptable RPM on startup.

Next, remember if you fill the small onboard tank and have a regulator between the supply tank and the onboard smaller tank...the regulator will not allow sufficient pressure into the small canister to give a proper start.

Fill the onboard tank, close the valve completely, initiate a start and slowly open the valve until the propane ignites.

Good luck!!

farrel

Hi Ron,
First: Make sure you are not introducing liquid propane into the motor....what type of propane are you using ??
Yes,I am sure that there's no liquid is introduce into my motor,guarantee.....I don't know the type of my propane. It si the sameproduct as I used before this and it worked just fine

Do be sure your onboard start battery is healthy, as a weak battery will result in lower than acceptable RPM on startup.
I always fully charged my battery before I start the motor (it reads 8.1 on the HDT)

Next,remember if you fill the small onboard tank and have a regulatorbetween the supply tank and the onboard smaller tank...the regulatorwill not allow sufficient pressure into the small canister to give aproper start.
Idon;t have any regulator between on-board tank and gas supply tank, theonly regulator is between the motor and the solenoid gas valve

Fill the onboard tank, close the valve completely, initiate a start and slowly open the valve until the propane ignites.
Ialready did this. Open the valve gradually until I hear the gas burn.What happened next was the starter hung in 25K (it won't raise) and itshut down by itself cause the on-board tank is empty or suddenly therpm jumped to 28K and raise rapidly to 55K (idle speed) causing flameout while the temp is still normally low (490C).

Thank you,

Farrel

Wren Turbines USA

My Feedback: (39)

Is the motor going in to ramp, ie: is fuel being introduced to the motor. Check that the fuel solenoid in correctly plugged in...and then you can try bypassing the fuel solenoid........to see if fuel is flowing.

farrel

Yes, the fuel did deliver to the motor, but....after the temp is around 280C and up, below that, the fuel didn't deliver to the motor.
Is this correct???If is this correct. then why after 280C (say 290 or 300C) when the fuel was delivered to the motor, the temp jumped to around 350C and keep on increasing while throwing some flame out of the exhaust.
What is the normal starting time??from the time ECU says Glow Test to Running??mine was 20s+ with condition adjustable gas valve only 1-1/4 turn.
Thank you,

Farrel

Wren Turbines USA

My Feedback: (39)

Farrel,

We have covered the obvious...so......

Time on the motor?

Type of fuel pump: Hausel or Flightworks

siclick33

I don't want to jump in on a Wren support forum but have you done anything other than change the propane tank? Are the fuel and gas lines the correct way round?

farrel

Siclick33
Yes, I do already change the propane tank for the gas supply, twice and already recheck the fuel connection. If it's not in a correct manner, I won't start right??But my motor still can start, the only thing that come to my concern is, there is always a flame in the start sequence.
Ron,
The motor is Flightworks type. I have re-read the manual that come with the motor, it is said that, after 100C, the fuel will start ramp,i.e : the fuel will start to introduce to the motor. and the starter will continue to rise until 30K rpm. Compare to this, mine is introduced when the temp is above 280C, and rpm is 28K (it stands there for a moment, 5-7 seconds), and after fuel was introduced, the rpm rise quickly to 30K and to 55rpm. This quick rise in rpm that (I think) causing flame out.
So, is it true that the fuel is introduced when the temp (and HDT says) 100C??

Wren Turbines USA

My Feedback: (39)

Let's go back to the beginning...

The motor started and ran fine until you changed propane tanks??

farrel

Firstly,
I didn't use on-board propane tank, so when the propane in the propane tank start to deplete (the pressure also deplete), I need to turn the adjustable valve more to release more gas to the motor. SO the gas valve opening is now bigger than the first time I got the motor. My mistake is, I didn't record how many turns I have made.
Now, I wanna use on-board tank. I tried it first with the new propane tank. First trial, I got very bad hot start coz the valve opening was too big, so the engine starting is very rapid and uncontrollably.
I fully close the gas valve, and open a little just as a "hiss" sound heard. The motor did spin and the gas did burn, but it hung in 25K, no fuel was introduced.
I did several trial, and the best is 1-1/4 turn (even there is still flame out), but the highest temp is "only" 490C, far from the limit (840C). But still, I'am not satisfied yet, since it still has flame come out from my exhaust.

Wren Turbines USA

My Feedback: (39)

Okay, now we are getting someplace!!
The 44 doesn't like a lot of propane. With the fast temperature rise (to much propane) the ECU is not allowing a proper ramp, in other words....it sees an increase in temp so the ramp is delayed because the EGT is telling the ECU that the temps are rising okay......but it is from propane and not fuel.

Please decrease the amount of propane and retry..

farrel

Ron,Maybe, instead of I do some trial here and there, you can point me to a value (or turn) of the new wren 44 (is it 1/4, 1/2 or 1 turn), in other words, I wanna return to factory setting, and I believe you have this setting as you alaways test the engine on the bench before left your shop.Please let me know.Thank you,

Wren Turbines USA

My Feedback: (39)

On the test runs of every motor, the needle is closed. The start is initiated and then the needle is opened until ignition. There is no "set value' as all installations are quite different.

So: Begin the start,

When the HDT indicates"glow test" sllloooowwwlllyyy open propane needle valve until you get
the "pop"of the propane ignition. That's all there is to it!!

farrel

Aright Ron,Will try to do as your advice and let you know.Hope it all resolved..Thank you anyway...

farrel

Hi Ron,
Just did what you advised, and it run very very smooth... no flame out again....
Again, thank you very much,
Warm regards,


Farrel

Wren Turbines USA

My Feedback: (39)

Great news!!