Basically, completely rework the Wrench Wand to function like a Gremlin Mandar. The normal attack will remain the same, but the charge attack will be reworked. From 2* to 4* the charge attack will heal the Allie that your target. In addition to your fellow knights you can heal turrets and any spawned allies too.
At 5* the path will split into 2 different line's. The Mender Staff or the Mender Wand. The Mender Staff's charge attack will be the same as the 2-4* counterparts but stronger. The Mender Wand will summon a Yellow Circle which heals AoE over a period of 5 seconds. 5 bursts of small amounts of health. However, the wand will have a much longer charge. Comparible to gran faust.
The Mender Wand can heal yourself but the Staff can't.
Weapons like this would be a great wand to start a pure support class in Spiral Knights.
In Spiral Knights, all sources of healing are limited. Sometimes there are healing plates between battles, but in general the only way to heal yourself is by defeating enemies.
I'm not against a healing weapon, but you'd need a way to limit the amount of uses. It could draw from heat, your own health pool, have a chance to recharge from kills, etc etc.