We just had our second mattress chamber rupture from change in altitude and temperature. (I've noticed the pressure does go up from the engine heating while traveling as well as changes in altitude.) Since our bed is still under warranty, we are getting another free replacement. BTW, the lady that helped me on the phone today said she has had several people calling in with the same issue this summer.
However, it just bugs me that a company can charge you $1500 for a product that will be changing altitude/temperature and it not have a safety pressure relief valve in it. They just say to let air out before you travel. I think there must be a better solution, so here is my thinking:
I called Sleep Number and asked them what the actual pressure in the mattress is with a setting of the maximum 100. They said it is 0.6 psi! So, if you assume the max working pressure is 0.6 psi and you design it with a safety factor of say 3X, the burst pressure would be 1.8 psi. Looking at the atmospheric charts, the change in atmospheric pressure from sea level to 7,000 ft (here in Colorado Springs) is approximately 3 psi. Since the mattress is fabric covered, it cannot stretch, so there is no relief from volume change. (That is why your tire pressures don't change as much with altitude.) As a result, the pressure is 6 times the working pressure. Add in some heat from the engine, and it was most likely even higher. We had one of the two chambers burst, so I assume the real failure is probably 2.5-4.5 psi based upon two failing, and one not, on me
After a bit of searching on the internet, I found a 0-20 psi adjustable pressure relief valve for $4.44.
It can be found Here.
So my plan is to purchase two of these and pick up the appropriate fittings, and put them in the lines that go to the chambers under the night stand near the pump. Set the release point to be just at/above the 100 setting on the mattress, and I should be good to go!
If anybody has any thoughts on this, or has gone through this and found a better option, I would appreciate hearing about it. I think it is cheap insurance to protect the system.
Jeff
However, it just bugs me that a company can charge you $1500 for a product that will be changing altitude/temperature and it not have a safety pressure relief valve in it. They just say to let air out before you travel. I think there must be a better solution, so here is my thinking:
I called Sleep Number and asked them what the actual pressure in the mattress is with a setting of the maximum 100. They said it is 0.6 psi! So, if you assume the max working pressure is 0.6 psi and you design it with a safety factor of say 3X, the burst pressure would be 1.8 psi. Looking at the atmospheric charts, the change in atmospheric pressure from sea level to 7,000 ft (here in Colorado Springs) is approximately 3 psi. Since the mattress is fabric covered, it cannot stretch, so there is no relief from volume change. (That is why your tire pressures don't change as much with altitude.) As a result, the pressure is 6 times the working pressure. Add in some heat from the engine, and it was most likely even higher. We had one of the two chambers burst, so I assume the real failure is probably 2.5-4.5 psi based upon two failing, and one not, on me
After a bit of searching on the internet, I found a 0-20 psi adjustable pressure relief valve for $4.44.
It can be found Here.
So my plan is to purchase two of these and pick up the appropriate fittings, and put them in the lines that go to the chambers under the night stand near the pump. Set the release point to be just at/above the 100 setting on the mattress, and I should be good to go!
If anybody has any thoughts on this, or has gone through this and found a better option, I would appreciate hearing about it. I think it is cheap insurance to protect the system.
Jeff
